Engine Roughness

[Decado 10+ year member]

Well, lately I've been having a problem with my car and I don't really know where to go to figure it out so i might as well try here. I'm driving a 93 Mercury Sable with 112k miles on it.

The problem is, my engine seems to be running very rough, and the problem seems to be mainly in park idling but still is a problem while idling at a stoplight or w/e, just not as bad. I am also getting about 13 miles per gallon (no, I do not drive like an idiot, and I do get regular oil changes and add oil when it is needed). Now, I do have a big hole in the exhaust (where the headers bolt on to the rest of the exhaust, not sure what it's called, is almost completely rusted off) but I do not think that is the problem because then i would be getting a louder noise, but it would be smooth still if the engine is fine am i correct? Now, it seemed as though it could be misfiring, but doesn't sound very definitively like it is misfiring, basically it will get loud for a second then get a lil quieter and sometimes it is loud for a few more seconds and quieter for a few more, it seems to be completely random. Now when I accelerate It doesnt seem to have this variation in sound, but it still sounds rough, plus it has somewhat of a winding up sound to it, but i'm guessing this would be the belt (I could be wrong though). Another thing I noticed is that when i sit in idle for a long period of time (train or something) I can slightly smell burning oil once I start moving again. I tried replacing my spark plugs and wires and this did not fix the problem. Air filter is clean, I cleaned out the MAF sensor with non-residue electrical spray and that didnt help, there is no smoke coming from the exhaust (white or black). The fuel pump sounds like it is running fine (when i have my backseat off I can hear it), but the car does struggle to stay running when i first start it on very hot days (90+ degrees). This is about all I can think of that would have to do with the problem. Does anyone know what could be wrong here?

One more thing I am wondering about (that i'm not too worried about at the moment) Is when I accelerate and the car switches gears (automatic) I have to hit the gas harder to get to the next gear (or if i'm accelerating fast for some reason it just jerks forward), the car also jerks forward when i'm slowing down (worst from 2 down to 1). This sounds like the transmission to me (which scares me, lol) but it doesnt seem to get progressively worse. Does anyone have any ideas on this problem also?

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[88sentra 10+ year member]

Autos have a kickdown system, when u punch it, the trans drops down a gear. In my car i feel it jerk foward when it kicks down so yea it migh be that.

Cheers 88sentra

 

[Decado 10+ year member]

Autos have a kickdown system, when u punch it, the trans drops down a gear. In my car i feel it jerk foward when it kicks down so yea it migh be that.

Cheers 88sentra

What do you mean when you punch it? When i hit the brakes or what? Because it's when hitting the brakes and acellerating. And also, anyone have ideas on the engine roughness?

 

[r1dermon 10+ year member]

engine roughness has nothing to do with your exhaust system in this case, change your plugs and wires, if that doesnt work, find your coil pack(s) and turn the car on at night in complete darkness and look for a spark. if that doesnt work, check your fuel lines and fuel injectors, they should all click when applied power.

the transmission problem is easy, and yet, it can be the most expensive if not dealt with right away. take your car to a shop and get a tranny flush, not just a tranny oil change, get a flush. what's happening is, your filter is dirty inside your tranny, so the fluid doesnt circulate as quickly, causing an upshift(which is run on pressure between clutch packs) to be hard and making it only possible at higher rpms. when you do the tranny flush, make sure they take the filter out and either clean it really well, or put a new one in. should run about 100 bucks...your ignition situation can be solved for less than 200 bucks for new wires, plugs and coils...good luck and keep us posted.

 

[Decado 10+ year member]

engine roughness has nothing to do with your exhaust system in this case, change your plugs and wires, if that doesnt work, find your coil pack(s) and turn the car on at night in complete darkness and look for a spark. if that doesnt work, check your fuel lines and fuel injectors, they should all click when applied power.
the transmission problem is easy, and yet, it can be the most expensive if not dealt with right away. take your car to a shop and get a tranny flush, not just a tranny oil change, get a flush. what's happening is, your filter is dirty inside your tranny, so the fluid doesnt circulate as quickly, causing an upshift(which is run on pressure between clutch packs) to be hard and making it only possible at higher rpms. when you do the tranny flush, make sure they take the filter out and either clean it really well, or put a new one in. should run about 100 bucks...your ignition situation can be solved for less than 200 bucks for new wires, plugs and coils...good luck and keep us posted.

Ok, first off, I just replaced spark plugs and wires so i doubt it's that, second what are coil packs? And the fuel injectors, that is where those silver lines go into the engine am i correct, and i just listen to each one when i hit the gas or what, and do i do this in park, nuetral, drive? And as for the transmission, I just replaced the tranny filter and gasket about 5k miles ago, now when you say do a flush do you mean just drain the fluid and replace it or actually flush it out with something, because when me and my buddy replaced the filter and gasket we drained everything and refilled it.

 

[r1dermon 10+ year member]

ok, if you trace your wires from your spark plugs back to your distributor cap, in the center of the distributor cap will be a coil wire, its a lone wire, not connecting to any spark plug, rather, it goes off in its own direction, trace this wire and you'll fine your coil. if your coil is arcing along a piece of metal or something, it will lose a lot of spark power, which is why it would run ratty at lower rpms. when it discharges, it will emit a noticeable spark. so turn your car on at night, keep it in park, and open your hood, make sure its good and dark, if you notice any blue sparking coming from the coil, then you've got a problem. if not...then it must not be ignition related. how old is the gas and how many tanks has it been performing like this for? if less than one, go to an auto store and get some dry-gas and pour it into your tank, just in-case there's water in there. the transmission sounds serious if you already had it flushed...i'd try it again though...how many miles are on it and how hard do you drive it? if you beat on it, eventually the bands which actually convert the engine power could be worn out. it sounds like low hydraulic pressure though...fuel injectors are directly off of your fuel rails...they might be under your manifold, so it could be difficult to get to them...anyway, you can find them by tracing either the gas lines under the manifold, or tracing 6 sets of wires(assuming its 1 injector per cylinder and 6-cylinders) under the manifold. they'll connect with square connectors and they all are connected to fuel lines. testing the injector is as easy as running your car so it runs like crap for a few minutes, and then pulling the spark plugs. look at the spark plugs and determine if one or two have been misfiring. do this by looking for blackened terminals on them or a lot of soot. regularly firing plugs should be fairly dry. if any oil is on them...bad sign.

 

[Decado 10+ year member]

ok, if you trace your wires from your spark plugs back to your distributor cap, in the center of the distributor cap will be a coil wire, its a lone wire, not connecting to any spark plug, rather, it goes off in its own direction, trace this wire and you'll fine your coil. if your coil is arcing along a piece of metal or something, it will lose a lot of spark power, which is why it would run ratty at lower rpms. when it discharges, it will emit a noticeable spark. so turn your car on at night, keep it in park, and open your hood, make sure its good and dark, if you notice any blue sparking coming from the coil, then you've got a problem. if not...then it must not be ignition related. how old is the gas and how many tanks has it been performing like this for? if less than one, go to an auto store and get some dry-gas and pour it into your tank, just in-case there's water in there. the transmission sounds serious if you already had it flushed...i'd try it again though...how many miles are on it and how hard do you drive it? if you beat on it, eventually the bands which actually convert the engine power could be worn out. it sounds like low hydraulic pressure though...fuel injectors are directly off of your fuel rails...they might be under your manifold, so it could be difficult to get to them...anyway, you can find them by tracing either the gas lines under the manifold, or tracing 6 sets of wires(assuming its 1 injector per cylinder and 6-cylinders) under the manifold. they'll connect with square connectors and they all are connected to fuel lines. testing the injector is as easy as running your car so it runs like crap for a few minutes, and then pulling the spark plugs. look at the spark plugs and determine if one or two have been misfiring. do this by looking for blackened terminals on them or a lot of soot. regularly firing plugs should be fairly dry. if any oil is on them...bad sign.

Ok, first off, when you say it sounds like low hydraulic pressure you are talking about the fuel injectors right? That part kind of confused me. And since it's been driven a while after changing spark plugs and stuff do i even need to let it run a few mins before I check the spark plugs? And if the spark plugs have oil on them, what does this mean?

 

[Blunt 10+ year member]

well think of it this way. the spark plug goes in the top of the head where gas goes and the piston compresses it and the plug fires. should there be oil in there with it not jsuta little but enough to coat the bottom of your plug. Flush the tranny not jsut change the fluid. ford trannies for the sable/taurus are ****. you are at about its lifespan. Feel lucky my sable tranny went out at 85k. what motor do you have? the 3.8? no he is not talking about the injectors low hydrolic pressure is in the tranny.

 

[SSS 18734 5,000+ posts]

My 88 Taurus has a rough idle. The Sable/Taurus are practically identical vehicles.

It's not so much of a problem, just a bit annoying. Plus the belt is sqeaky, which can be fixed temporarily fixed with silicone.

 

[Decado 10+ year member]

well think of it this way. the spark plug goes in the top of the head where gas goes and the piston compresses it and the plug fires. should there be oil in there with it not jsuta little but enough to coat the bottom of your plug. Flush the tranny not jsut change the fluid. ford trannies for the sable/taurus are ****. you are at about its lifespan. Feel lucky my sable tranny went out at 85k. what motor do you have? the 3.8? no he is not talking about the injectors low hydrolic pressure is in the tranny.

3.0 engine, which is strange because these engines are supposed to last a long time.

 

[r1dermon 10+ year member]

no engine is the same, and they do burn out early...but this is not a huge issue you have here. unless of course your engine is overheating and your oil is a milk color...then you can look for a new car/engine. anyway. the hydraulic pressure was referring to the transmission. inside the transmission is a pump. when that pump is filled with fluid, it pumps that fluid into the mechanisms of the transmission. the pressure caused by the pump, drives clutch packs together, which in-turn, spin an output shaft, which spin your axle, which spins your wheel. so basically, if your transmission is low on fluid, then the pump will not be able to pump a lot of pressure into the clutch's, causing them to slip. however, if it slips and there's adequite fluid in your transmission, and your filter is not clogged(which would slow down the pumping process) then it has to be a band or a worn out clutch pack inside the transmission, which if worn out, would cause the transmission to slip into gear...if that's the case, it'll gradually get worse over the next few months until its completely undriveable...

the fuel injectors are on the top of the engine...if you look at your valve covers(where you put your oil in) they're connected to your heads. under the heads is the engine deck and the pistons/cylinders. at the top of the head, or off to the side of the head, will be your spark plug. AROUND the same vicinity of the sparkplug, will be an injector if it is direct injection. if not, your injector will be at the bottom of your manifold plate right under your intake manifold.

if you trace the middle wire on the distributor cap back to where it begins, you'll find the coil pack. look for this to spark when the engine is on and idle in park.

it's possible that you got a bad set of wires or plugs when you put them in...or, maybe you didnt gap the plugs, if they werent pre-gapped. when you and your friend put the plugs in, did you gap them with a gapping tool? or did you just bust em out of the box and throw em in? that could be a problem...im just trying to rule things out here. i'd check to make sure you didnt overfill your oil, check the color of the oil, check the plugs, if they're fouled(oiley) grab a new set or take a blow torch to them for a minute or so each. and DEFINATELY, start the engine cold, with cold plugs, let it run for a minute or two, then kill it and grab the plugs out fast, test each temp with your fingers or a digital thermometer.

keep us posted.

 

[Decado 10+ year member]

no engine is the same, and they do burn out early...but this is not a huge issue you have here. unless of course your engine is overheating and your oil is a milk color...then you can look for a new car/engine. anyway. the hydraulic pressure was referring to the transmission. inside the transmission is a pump. when that pump is filled with fluid, it pumps that fluid into the mechanisms of the transmission. the pressure caused by the pump, drives clutch packs together, which in-turn, spin an output shaft, which spin your axle, which spins your wheel. so basically, if your transmission is low on fluid, then the pump will not be able to pump a lot of pressure into the clutch's, causing them to slip. however, if it slips and there's adequite fluid in your transmission, and your filter is not clogged(which would slow down the pumping process) then it has to be a band or a worn out clutch pack inside the transmission, which if worn out, would cause the transmission to slip into gear...if that's the case, it'll gradually get worse over the next few months until its completely undriveable...the fuel injectors are on the top of the engine...if you look at your valve covers(where you put your oil in) they're connected to your heads. under the heads is the engine deck and the pistons/cylinders. at the top of the head, or off to the side of the head, will be your spark plug. AROUND the same vicinity of the sparkplug, will be an injector if it is direct injection. if not, your injector will be at the bottom of your manifold plate right under your intake manifold.

if you trace the middle wire on the distributor cap back to where it begins, you'll find the coil pack. look for this to spark when the engine is on and idle in park.

it's possible that you got a bad set of wires or plugs when you put them in...or, maybe you didnt gap the plugs, if they werent pre-gapped. when you and your friend put the plugs in, did you gap them with a gapping tool? or did you just bust em out of the box and throw em in? that could be a problem...im just trying to rule things out here. i'd check to make sure you didnt overfill your oil, check the color of the oil, check the plugs, if they're fouled(oiley) grab a new set or take a blow torch to them for a minute or so each. and DEFINATELY, start the engine cold, with cold plugs, let it run for a minute or two, then kill it and grab the plugs out fast, test each temp with your fingers or a digital thermometer.

keep us posted.

Hmm, i never gapped the plugs, what does this entail?

 

[r1dermon 10+ year member]

on a spark plug, there's a flat piece of metal, and a bent piece of metal a short distance away from it, this is the gap which makes the actual spark, since every electrical current needs somewhere to go, in order for it to output a spark which will effectively ignite the gasoline, the two terminals have to be a certain distance away from each other. this is known as the spark plug gap. in order to gap your plugs, go to pep boys, autozone...basically any autoparts store, and buy a gapping tool. look up the specs for your motor, or the plugs, and then gap them with the tool. its basically a round metal disc with a wedge which gradually increases its side around the circle, it's labeled off so you know how big the gap is. it doesnt take a lot of force to gap a plug, so just use your hands to force the wedge inside there. try that with a set of new plugs, buy a few sets of cheap plugs, most likely you're going to foul out a set or two in the process of fixing your car/diagnosing your problem.

 

[Decado 10+ year member]

on a spark plug, there's a flat piece of metal, and a bent piece of metal a short distance away from it, this is the gap which makes the actual spark, since every electrical current needs somewhere to go, in order for it to output a spark which will effectively ignite the gasoline, the two terminals have to be a certain distance away from each other. this is known as the spark plug gap. in order to gap your plugs, go to pep boys, autozone...basically any autoparts store, and buy a gapping tool. look up the specs for your motor, or the plugs, and then gap them with the tool. its basically a round metal disc with a wedge which gradually increases its side around the circle, it's labeled off so you know how big the gap is. it doesnt take a lot of force to gap a plug, so just use your hands to force the wedge inside there. try that with a set of new plugs, buy a few sets of cheap plugs, most likely you're going to foul out a set or two in the process of fixing your car/diagnosing your problem.

Thanks man, i'll try this out when i get some money.

 

[NJack2AF 10+ year member]

Hey r1, what happens when you overfill your oil? Is it extremely bad, or are we just talking new plugs? I think I may have overfilled because I thought it was leaking a lot more than it really was, and my car is idling pretty rough. Last time it was idling rough I had 5 burnt valves, so I'm scared....

BTW sorry to threadjack