172sport

iTrader: (6)

Right whats the most common cause for a part throttle missfire?

On boost its fine, but part throttle it occasionally dies until full throttle brings it back to life.
Its recently had a new pump so its doubtful its that.

My first thought was wet or damp components but i think thats been ruled out now.

I'm getting a few bits to swap out MAF, crank and cam sensor so will take it from there really, any advice welcome.


Cheers

scoobian

air filter and plug check, perhaps?

172sport

iTrader: (6)

Anyone?

djsparra

iTrader: (5)

I'll be interested in the answer to this one.

I've got the same problem, plus cold mornings makes it worse. I've checked plugs, new leads, cleaned boost control solenoid, new air filter, cleaned MAF and did the check, unplug it and the car cuts out like it should. It's still doing it!!

What do we do now? HELP!!

djsparra

iTrader: (5)

Sorry to take over this post, but can someone please help us out, my car's started cutting out randomly now.

Bubbaroo

Plugs were the problem i had on my old classic. it would misfire under load, more so when hot but also cut out when cold. A new set of denso iridium plugs and a good clean of the boost controller and the maf sorted it out, went like a dream after.

djsparra

iTrader: (5)

Yeah i've done all taht but it's still doing it, Grrrrr!

djsparra

iTrader: (5)

bump

saiklon

Throttle Position Sensor? Theoretically it could cause this.
Oxygen sensor? A dead 02 sensor will cause flat spots in power output at part throttle.

scotty2hotty

iTrader: (4)

My maf went on my last impreza all of a sudden with no warning,
The car run spot on while on tick over but wouldnt boost at all just spluttered and wouldnt rev, I unplugged the maf while running and it cut out as it should as someone told me that is how you test the maf so i then thought the maf was ok.
Turns out the maf sensors are s**te and are a common probem and that come from a subaru dealer themselves, subaru said they advise people to change them every 5 years. point is i changed my maf and it was fine.

172sport

iTrader: (6)

Well got hold of some 2nd hand sensors, changed the cam and crank sensor. Did a 20 min test drive and no faults. Next day i visited a mate in Lincoln a 60 mile round trip, on the way there it never missed a beat but on the way home it was a total pig spluttering and dieing...............................

That night i changed the MAF to the 2nd hand one, again another 20min run out no issues at all.

In the mean time i've bought a new set of NGK plugs £30 plan to fit those when i get time.

Well went out today for a couple of hours, no issues to report and it never missed a beat. I'm guessing the MAF was failing intermittantly, i still dont trust it fully yet but fingers crossed its not going to play me up at Cadwell on Sunday as i'm all paid up for a trackday.

djsparra

iTrader: (5)

Hmmmm, Sounds like you've solved it mate, those were the sensors i was going to try first, cam and crank first. I know of an STI in a local breakers, might have to take a trip down at the weekend. Good luck on the track day.

172sport

iTrader: (6)

TBH i would get a MAF first.

I was lucky cos i got crank, cam and MAF for £40

mit

iTrader: (10)

I had very similar on my last scoob, fine on boost, misfiring off.
Turned out to be a leak in the pipe to the intercooler. When on boost, it was enough to overcome the leak, off boost it was upsetting the ecu as it was drawing in air after the maf/turbo, so fueling was all off.

djsparra

iTrader: (5)

oh cool i'll check the interco. Pipes as well. I get black smoke also when it plays up which lead me to the MAF unburnt fuel, not enough air? Nice one guys! Cheers