[chuckoff]

I did every imaginable check on the engine, the leak down went well.. there are no torn hoses, new intake manifold gasket, new spark plugs, new fuel injectors, new coils.... so at this point i tried to drive it with its issues, i noticed that when i pressed the gas lightly the car would barely move then have a surge in power, also when i press the gas to take of from a red light it feels like the car is on a rumble road for 2 secconds, then goes back to normal, and the missfire/sputtering happens only at idle and i also noticed that the engine sputters alot when going about 50mph...it wont go any faster.... lastly the car has a serious lack of power, and some awful mpg (the least of my concerns).

can it be a fuel pump?.... i mean the car does have 250k miles on it

Is the only code P0303? Fuel pump would most likely cause multiple cylinder misfires. One cylinder misfiring on a 4 cylinder car is a pretty big deal and will cause a major decrease in performance. Is it still just #3? Have you checked continuity and resistance between the coil and injector wiring to the ECM as well as checked for shorts to ground? I know you said leak down was good but, did you check valve clearance? If everything is OK this leaning towards an ECM. Also, maybe even sway the new parts to different cylinders. New does not always mean good.

 

[Steve9661]

Is the only code P0303? Fuel pump would most likely cause multiple cylinder misfires. One cylinder misfiring on a 4 cylinder car is a pretty big deal and will cause a major decrease in performance. Is it still just #3? Have you checked continuity and resistance between the coil and injector wiring to the ECM as well as checked for shorts to ground? I know you said leak down was good but, did you check valve clearance? If everything is OK this leaning towards an ECM. Also, maybe even sway the new parts to different cylinders. New does not always mean good.

Did you ever fix the misfire?

 

[kbod]

Did you ever fix the misfire?

no, as a matter of fact i went a head and replaced the ecu and the fuel pump, the issue did not change at all

 

[Adubya]

man I have new reman engine that doing that on cylinder 4. at first it was p300-304 then 303 and 304. Now 304 only. up and down blah blah.
now my fuel pump is out I think(currently working on it.

check your coil connectors. I just put new ones on and haven't been able to start the car yet. They were so brittle and broken

 

[Mannyjb90]

It's not the fuel pump. And the ECU is NOT under the battery, though the advice of checking cylinder 3 circuit from the ignition coil to the PCM, and the injector to the PCM, are the best bet. If you've checked and replaced all these other items, and you did the checks correctly, then it's either circuits or wiring. Another thing you might want to check is the balance shaft, based on what you're description of the engine behavior is... but don't go and check this until you're absolutely certain all other avenues have been checked, as it's unlikely that would cause your misfire, but not impossible, since first order vibrations in the engine can cause your sensors to mis-read.

 

[Kidroc666]

crank or cam sensor..

 

[bharnois]

The coil pack connectors get pretty (Extremely) brittle. Do you have any broken or missing clips? Have you tried pushing the individual wires into the connector? Those are only about 6 bucks at the dealership. (I had a couple of problems similar to yours that all went away with the clip swap. The connectors were so brittle I didn't need a pin removal too, just some needle nose that I gently chipped them apart. It didn't take much!).