02 wrx stutter/ misfire

the setup: 02 wrx complete swap into 95 impreza L. 96,000 miles, header, uppipe, turbo back exhaust, ap stage 2, k&n filter, egt sensor resistor fix.

the problem: the car stutters and misfires mostly while at a steady cruising speed but sometimes during acceleration in 1st and 2nd gear. it also has cut out a couple of times under boost, but it normally does not cut out under boost.
the first couple of times i drove the car i was getting random misfires codes(all cylinders at different times and combinations). cleared those codes a few times and now it still does the same problems as before but now i don't get any misfire codes or any trouble codes other that the one or two i get from the swap( emissions stuff on the gas tank)

possible solutions: new regapped plugs( had them in already but the gap was .035 when it should be .030). coil packs? (but seems odd that all of them would be setting a mifire code?)
crank sensor? i know this tells the ecu whether cylinders are misfiring( could be why i have no misfire codes, but then i should have a code for the cranks sensor?)
top engine clean? (seafoam)

other than that i'm stuck since i am new to this newer style of motor and electronics, and common quirks they have. so any ideas or suggestions on what to do is greatly appreciated.

thanks in advance, ryan

 

run some seafoam and see.. could be sticking valves?? regap your plugs... narrow it down...

 

I had similar issues recently. My problems were,

Busted crank sensor and bad coil packs. Ide swap those out for new ones and see if that works.

 

i don't have time tonight to try anything tonight but i will tomm.

when you guys run seafoam do you let the car idle and suck in the seafoam or do you just pour the required amount down the vacuum line and let it sit for 5-10 min?

also i think i am going to clean the maf too, but i need to find the right stuff to clean it.

would a bad o2 sensor cause this? i know a couple of the wires on the front o2 got some of the coating rubbed off when i pulled out the motor, not sure if this would affect things or not.

 

I am having similar issues and was thinking it may be the crank sensor? Did your car backfire and idle really rough?

 

Get rid of your K&N and clean your MAF sensor with some electronics cleaner.

 

Yep, both.

 

the thing with my car is it doesn't idle bad, if you push in the clutch right when it's stuttering the car will almost die but other than that it idles fine

 

for sea foam, let it suck it in at idle. there should be a tiny little vacuum hose coming off the center of the intake manifold on the 2.0l. This is the best place to go from since it will fairly evenly distribute the sea foam to each bank / cylinder.

As has been said I would regap the plugs, check the coils, and sensors. I highly doubt that an O2 sensor would cause this. You might also check your connections between the crank sensor and the ECU. When I had misfire issues it was from a loose wire at the ECU.

 

thanks martin, i will be putting the new plugs in a little bit, then run the seafoam. and then i am heading to work to run it on the lift with our good scan tool on it to see if i can pinpoint this problem.

i cleaned the maf last night and it didn't help(it was pretty dirty too)

 

coil pack coil pack coil pack

 

i want to do a few little things before i drop 300+ for all new coil packs plus i can't get them any sooner than monday or tuesday because erik has to order them. i just have to get the order placed today :biggrin:

 

Somebody has to have a few spare's you can try out first, no?

 

too bad i don't need any coils!!!:biggrin:

problem fixed- front o2 sensor was bad.

hooray!!!:biggrin: