Wow... so much failure on replies in this thread. Some way may true, but most is not on a Honda.
There is no MAF sensor. There is a MAP (Manifold Absolute Pressure) sensor. It does not require cleaning, or maintenance. Leave that alone. It could crack very easily where it screws onto the throttle body, or you could damage the O-ring and sensor tip.
Get your codes pulled at AutoZone.. it's free. Your CEL has been on, so you do not know if there was something else that popped up.
Those "good" spark plugs do not do anything for you. Honda's run fine on the OEM NGK plugs.
Take a look at the plug wires, if they're cracked or obviously worn, replace them. One way to check them is at night, or in the dark. Open the hood and look at the plug wires... if you see little sparks arcing off the wires, they're shot.
Pull the spark plugs, and see how they look. If they're a little grey/white, you're lean, if they look dark, you're running rich. Because you probably have Iridium plugs, they'll probably show they're a little lean, because they're a hotter plug. A normal worn plug will show light brown or a tint of redish tan color.
Pull the distributor cap, and see if there's any carbon buildup, as well as the point on the rotor. Are those parts still original?
cvjp417, I don't know who told you having a short(er) intake will make you run lean, but they're an idiot. It doesn't.
Go to Advance Auto, pick up a can of Sea Foam. Use 1/3 in the gas tank, 1/3 in the oil, and the last 1/3 into the intake. SLOWLY pour it in while the car is idling, shut car off, wait 5 minutes, and start the car back up and take it a couple miles wide open throttle. You'll be amazed the **** and all the smoke that blow out of the exhaust.
The fuel filter is very simple. For mine, it's 3 10mm bolts holding to the bracket, and a banjo bolt holding the fuel line on to/from the fuel rail. Can be done in 5 minutes. Take the gas cap off to relieve pressure before doing it, pull the PGMFI fuse and give it a couple cranks, your fuel system is then unpressurized.
Change your PCV (Positive Crankcase Ventilation) valve, too. You'll actually burn oil if it's that bad. the use of a PCV valve is to release pressure from the motor, letting it breathe better. If that little valve is gummed up, it can't let any pressure out. If you happen to be lucky like me, and no one has one in stock, you can take it out, and soak it in gas or shoot it with Carb/Choke cleaner. Shake it, if you hear rattling, it's good, and that means the valve is working.
EGR valve won't really do that.. if it was, it would run like **** on part throttle and cruising.
Last thing I can think of is the 02 sensor(s). Like I said before, get the codes pulled. It could be the 02 heater circuits, or the sensor itself is fouled. If it's fouled, it's not going to get a correct reading, and it's just going to dump more fuel in. The 02 at the header is the upstream sensor, used to measure fuel burn ratios in closed loop operation. Anything over 1/2 throttle, it's going to read from the down stream sensor (in the test pipe), because the upstream can no longer read them fast enough, so it reads the exhaust gases. IMO, get rid of the test pipe, and get a high-flow catylic converter, such as a Car-Sounds cat. When you actually put an exhaust on the car, it's going to sound super raspy and really loud with a test pipe on there.
