Still misfiring
 

Hi people,

Need some assistance with this,

bought a wrx 2002 bugeye with 80,000 miles on the clock just before xmas, with a misfire...was running like limp mode all the way home until i got a sudden boost of power, and it drove pretty much alright, sluggish in lower end but great in the top....decided to put new plugs and get a new coil for cylinder 4 as its bringing the eml on and the code is the c4 misfire.....

even after new coil and plugs its still misfiring -showing misfire on cylinder 4 again...

Wondered if it could be a seal leak, earth issue or a sensor somewhere?
any ideas people?

huge thanks as always

Ste
2002 bugeye wrx

Can you actually feel it misfiring, or is it just what the engine light and code reader tell you? NPS switches on bugeyes are well known to throw misfire codes when the engine isn't actually missing.

are you sure you didnt damage the old coils changing the plugs ?

Plug gaps ?
I went through loads of things looking for a misfire , cutting out issues on my rally car , shut the plug gaps down by 0.01mm and it cured it !

it seems real lumpy in the low end revs, until boost kicks in its quite sluggish and every now and then you can feel the misfire

I'll ask the garage that put the new plugs in what space they used, worth a try! thanks man

showing as misfire in cylinder 4 again, fitted a new coilpack to c4 and still got the same issue,

Checked the earth connections today, seemed fine, then went for a drive and it kept giving me intermittent power, misfiring and back to normal, so i made sure the earths were clean and tight, seems better, but still misfiring now and then.,...

this is baffling me! short of checking every wire i've no idea what to do next!!
i keep seeing the eml flashing now and then too.

cleaned the maf
fuel filter is clean
brand new plugs
new coilpack for C4 (still showing the misfire)
earthed well
fuel pressure is good
no apparent splits in wires anywhere


any other ideas?

did you clean the maf because the readings were off or because it looked iffy? Sometimes cleaning the maf will end it's life and just add new problems to work on.

What's your battery voltage looking like and is there anyone nearby has a laptop they can plugin to check for other codes/logging data?

Have you checked that it's not a sticky injector as well? If the car is lumpy when idle if you can get an injector disconnected one by one and see if the note changes (should get worse each time an injector is removed)

So what error is the ECU seeing, its even giving you help with the EML on lol

Hi mate, i cleaned the MAF as i was advised to! didnt seem to effect anything either way, (its always running intermittent power, its as if a wire keeps connecting then disconnecting resulting in random power)

havent checked the voltage of the battery, could i use a generic multimeter for this?

havent tried disconnecting the injectors, (it runs fine at idle, but runs sluggish in lower end when setting off etc) is that something easy to do?

thanks for your help, its doing my head in now and using loads of fuel!!!

do you mean what codes is it firing out?

im getting the p0304 & p0304 p (after clearing codes this keeps coming back) and every now and then the eml flashes as if its currently misfiring...

have you tried swapping the coils round on that side of the engine to see if the misfire moves with the coil? Also don't forget one of the coils has an extra bracket on it to hold the o2 sensor wire in place so that has to be there as well.

i had the mechanic put a brand new coil into c4 (as this was the one showing the misifire) and the problem is still on c4 ....

is the extra bracket on cylinder 4? he also changed the plugs with new ones.

is it worth me buying a new o2 sensor or is it a waste of money? as i could end up buying loads of new parts and still not fixing the issue....

thanks for your help though matey!!! :)

no the bracket isn't part of the sensor it just holds the wiring in place but part of the bracket is used to make sure the bolt holds the coil in place. #4 should be the opposite side of that bracket.

if you had a mechanic do stuph did they make any other recommendations for you? I would still try swapping the coils to see if the misfire moves with it but if your not doing the work yourself you may be better trying to find a better garage to leave it with who will be able to diagnose better.

He said he would have to check all the wiring, im assuming the obd reader he had didnt show any other faults (o2/maf etc) its really bugging me now!!!

might be worth taking the hit and dropping the car off with a more subaru specialised garage - experience makes a big difference vs trial and error and possibly lots of parts you don't need

You might be right!!! scared to ask how much that would be!!! haha

Anyone know of a decent Subaru garage in Leeds or Yorkshire?

Thanks Bludgod!!!

Did the mechanic compare the plugs he took out? I would have had a borescope and good look in that cylinder mate. Might be more an issue of a sticking valve or something?