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View Full Version : Car keeps jerking/stuttering



LazyRider
06-10-2009, 08:52 AM
Ok so to start it off I have an 03 grand marquis about 106,000 miles. Sometimes when I accelerate up to like 50mph my car starts to like jerk or stutter a bit but after I push the gas some more it accelerates and rides fine. Also happens when I slow down a bit and then hit the gas it stutters more.

This is what I've done to the car since this started:
New Tires
New Spark Plugs
New Fuel Filter
Oil Change
Air Filter

Suggestions?

dman4486
06-10-2009, 08:55 AM
j0o has video of this?

Flipx99
06-10-2009, 08:55 AM
Transmission Clutch Solenoid?

Michael Savage
06-10-2009, 08:59 AM
You're scaring it. Drive more sensibly.

snoopdan
06-10-2009, 09:34 AM
why dont you just ask it whats wrong, if it's screwing up then it's most likely throwing a code.

jco1385
06-10-2009, 09:40 AM
i have a very similar problem and i'm going with faulty fuel pump. i haven't fixed it though, so i'm not 100%

but you should have a code. i dont because my chip eliminates the CEL so i dont get codes :crap:

crash9201
06-10-2009, 09:44 AM
go to autozone; theyll run the codes for free; just dont trust what they tell you to fix it

LazyRider
06-10-2009, 09:48 AM
Yea I tried the code thing at a shop nothing came up. My check engine light did come on before and my car stopped but then I turned it off and turned it back on and it went away so I took it to the shop that same day and tested it and nothing came up. This *****

John3000
06-10-2009, 09:50 AM
Bad fuel injectors :confused:

Was it an old Police car?

jco1385
06-10-2009, 09:52 AM
Bad fuel injectors :confused:

Was it an old Police car?

a marquis?

Skip01
06-10-2009, 09:58 AM
Something with ignition is my guess.

Its it seems like a real fast break up.

Did it do it before you did the stuff you did?

Put old wires back on if it didn't and see

Ellsworthz
06-10-2009, 09:58 AM
Bad fuel injectors :confused:

Was it an old Police car?

not a vic'

snoopdan
06-10-2009, 10:08 AM
prob transmission if no codes are being thrown.

SSS 18734
06-10-2009, 10:12 AM
Stuttering can be a large range of problems. When my car did it, it was a combination of two things:

1) Vacuum leak in the intake manifold
2) Faulty oxygen sensor

Flipx99
06-10-2009, 10:14 AM
prob transmission if no codes are being thrown.

This is what I thought...and the fact it is based on speed. It could possibly be ignition coils, but I am betting on the transmission solenoid because it is around where the tranny shifts. There is a thing called the TCC solenoid that goes bad. Another problem it has when this is going out is starting again after getting off the interstate. It "acts" as if the car is still in 3rd, 4th or whatever.

Flipx99
06-10-2009, 10:15 AM
Stuttering can be a large range of problems. When my car did it, it was a combination of two things:

1) Vacuum leak in the intake manifold
2) Faulty oxygen sensor

Wouldn't they throw a code?

njaykaplan
06-10-2009, 10:25 AM
The MLPS goes out often in those cars, otherwise known as the Neutral Safety Switch, but i doubt that would be your problem. I have a mark viii, and mines going out, and it will jerk occasionally because its confused about the gear, and occasionally when i'm cruising will pop itself into neutral for 2 seconds and then pop back into gear. Try to be a bit more detailed when it happens, in my car (same transmission, although yours is stronger) i've had to replace the 1-2 accumulator spring because it was snapped, and that created a really hard shift. Does it feel like your going over railroad tracks at 50? Could be the torque converter, do you happen to know if you use Mercon iii or mercon v in your car?

Flipx99
06-10-2009, 10:28 AM
The MLPS goes out often in those cars, otherwise known as the Neutral Safety Switch, but i doubt that would be your problem. I have a mark viii, and mines going out, and it will jerk occasionally because its confused about the gear, and occasionally when i'm cruising will pop itself into neutral for 2 seconds and then pop back into gear. Try to be a bit more detailed when it happens, in my car (same transmission, although yours is stronger) i've had to replace the 1-2 accumulator spring because it was snapped, and that created a really hard shift. Does it feel like your going over railroad tracks at 50? Could be the torque converter, do you happen to know if you use Mercon iii or mercon v in your car?

I am betting what Ford calls the MLPS, GM calls the TCC. It seems like they both do the similar things in that the tranny is "confused" about what gear it is supposed to be in.

I Like Waffle
06-10-2009, 10:29 AM
Drive the **** out of it and see if it gets better. Also, get some marvel mystery oil, thats always worked good for me for cleaning out carbs and fuel injectors and such.

LazyRider
06-10-2009, 10:31 AM
The MLPS goes out often in those cars, otherwise known as the Neutral Safety Switch, but i doubt that would be your problem. I have a mark viii, and mines going out, and it will jerk occasionally because its confused about the gear, and occasionally when i'm cruising will pop itself into neutral for 2 seconds and then pop back into gear. Try to be a bit more detailed when it happens, in my car (same transmission, although yours is stronger) i've had to replace the 1-2 accumulator spring because it was snapped, and that created a really hard shift. Does it feel like your going over railroad tracks at 50? Could be the torque converter, do you happen to know if you use Mercon iii or mercon v in your car?

Doesn't feel like going over train tracks it just starts like jerking and when I step on the gas and accelerate it stops. I'm not sure about the transmission fluid I haven't had to add any since I've had it.

njaykaplan
06-10-2009, 10:31 AM
I am betting what Ford calls the MLPS, GM calls the TCC. It seems like they both do the similar things in that the tranny is "confused" about what gear it is supposed to be in.

I think the fords have a TCC as well, but i'm not sure. I was just given a book larger than any school textbook i've ever seen about the lincoln mark viii, which has the same 4r70w transmission, and i'm reading through it and trying to learn how to diagnose my own car before i have problems. Btw, i got this mark viii for 800 dollars and already got my moneys worth over the 2 months :p:.

njaykaplan
06-10-2009, 10:33 AM
Does it happen specifically when its shifting from say 1-2 or 2-3 or 3-4? There are a lot of minor problems that are easily fixed with these trannys, if you have anyone that knows car mechanics close to you, it shouldnt be bad to fix.

NDMstang65
06-10-2009, 10:37 AM
Throttle position sensor can also cause the tranny to get confused as well..where it wants to kick down into passing gear but jump back up into over drive...

Take the car through town and just run it in a gear like regular drive or 3 (whatever that may be not sure on the car model) and see if it still does it...

I'd point towards the tranny sensor and/or the TPS...

PioneerSPL1990
06-10-2009, 10:41 AM
check the fuel Pump wires i had a rotten one in my 1994 mustang when i would get on it , it would studder or almost cut out.

Stephen_c
06-10-2009, 10:44 AM
Throttle position sensor can also cause the tranny to get confused as well..where it wants to kick down into passing gear but jump back up into over drive...

Take the car through town and just run it in a gear like regular drive or 3 (whatever that may be not sure on the car model) and see if it still does it...

I'd point towards the tranny sensor and/or the TPS...
x2
or idk if that car has a distributor or coil packs. if it has a distributor check the rotor and cap, if not check the coil(s).

John3000
06-10-2009, 10:55 AM
a marquis?

Tis my bad, did not have my coffee this morning. :crazy:

LazyRider
06-29-2009, 10:09 AM
Found the problem. There was a leak in the intake manifold. Looks like coolant is leaking down into where the spark plugs are. Car started smoking really bad yesterday and I popped the hood and looked and sure enough there was fluid leaking and it was causing smoke. Did some research and found out that the manifolds in these cars aren't very good and are pretty much cheap plastic and this happens a lot. Just posting this in case anyone else has the same problem.

nativeboy
06-29-2009, 10:21 AM
yea im having the same trouble with my car jerking and such but i replaced basically what you replaced and still doing it...

skull50016
07-14-2009, 01:31 AM
i would say check your tire balance, i had a similar problem, the car would shake back and forth and feel like it was gonna break, i would say take it to like pepboys or something and get them balenced

gnatnoop
07-18-2009, 06:00 AM
EDIT- LOL, didnt see you already figured it out...