Had a misfire problem with 2000 uk turbo, changed plugs and it cured it.
about 3 weeks later and the problem is back. I ve had suggestions of changing coil packs an HT leads, any more ideas? dont want to blow £150 and still have the problem.

 

hi mate u got any mods on ya car ie decat?? have u done an ecu check see if theres any codes showing??

 

Having had the same problem and changing the plugs the next thing i changed was the oxygen sensors on the exahust seems to have sort it out.

 

Hi guys, cheers for the response much appreciated, ive checked ecu and no fault codes present, only thing that is changed on the car from standard is the back box(and thats been on over 2 years now)
I'll have a look at the oxygen sensors, but surely i would get an ecu fault code (32 off the top of my head) if failing??
Cheers again i'll post back if i EVER find the problem.

 

What gap are your spark glugs set at?

At 0.8mm they caused a misfire but at 0.7mm the misfire stopped

Damo

 

Doubt its gaps on plugs as when they were first replaced there was no problem for about 3 weeks.

 

coil pack changed....sorted

 

NOT HAPPY!
its back again WTF is going on??
does anybody know if it is possible for a faulty coil pack to knacker a set of spark plugs?? this is the only thing i can think of.

 

Maybe the plugs are fouled from when you were getting the misfires?

 

changed plugs again on sunday morning, still no joy, seems to be drinking petrol now (worse than normal)

 

MAF maybe?

 

Might be worth checking the vac line to the fuel pressure regulator. I know this split on mine and caused a similar problem.

 

Possibly fault with connections or wiring or maf showing signs its on way out.
Check all conections to coil pack and engine wiring loom, disconect and check engine loom block connectors and make sure all is seated correct, also check plug leads are not arking.

 

I know it sounds too simple but had a horrendous misfire this weekend on full throttle. Pulled out the air filter and was pretty filthy. New one in and instant cure! Just a thought.

 

i had the same problem with mine and i had only had it 3days!! i did the same as you but it got worse so took it into a friend at merc he had it for aday and found that 1 of te wires going to the coil pack had brokern so a quick fix so i would check that

 

Cheers everyone, i think thr problem is definatley electrical, its off on a diagnostics computer on saturday, hopefully find the problem if not its off to dealers. i'll just have to live with about 10 mpg for the minute!

 

maf sensor mate. same problem on mine. no fault codes after diagnostics check. changed plugs / coil pack / fuel filter etc. changed the maf as last resort. sorted never looked back

hope this helps mate

mav

 

this is getting stupid... the car will not exceed 4000rpm now i am so pi$$ed off! can of petrol and a match at the ready.

 

That's not good, having said that I've been battling with a "continually varying" misfire on my 99MY (so same coil pack as yours) most times its fine, and then sometimes it just won't pull cleanly between 2K and 3K rpm, changed plugs and leads (twice - once at the dealership before I bought it and once since) and coil pack, still comes and go's, each time I 'fix' it its good for a while, then comes back (occasionally)

Simon

 

right well the 4k is the ecu's limp mode. get it to a speciailist and have then diagnose the problem, you could spend hundreds of pounds replaing this that and hte other and still not find it.

 

i know i have already said this but all the sytums you have is what i had on my v4 RA and it was just a wire thats under the intercooler area that had just brokern if i was you take to a specialist and get them to look at it and just mention it

 

if its using alot more fuel now i would change the oxygen sensors (Lambda Sensors) for the sake of about £40

 

Well its still booked in for saturday so hopefully will know after that.
as for replacing lambda help2003, i thought they were a lot more than £40 more like £100 +???

 

Lambda Sensors - Oxygen Sensors
SUBARU IMPREZA 2.0i pre cat direct fit lambda / oxygen sensor

 

its either lambda or maf if nots coil packs or plugs. 4 very common problems that occur in every subaru during their lifetime.

I changed lambda 4 times and maf 3 times in 3 years on mine, and then a coil pack cracked and i couldnt find what was wrong with it for 2 months..if only i knew about scoobynet back then : /

 

New maf fitted and its sorted!!! christ it feels quick again!!!