Hi People...Im a newbie with a lil bit of a Bl**dy annoying flat spot on my 2000 W REg UK Impreza Turbo. When i put my foot down (gently or bl**dy hard, it doesnt seem to matter?!) I get a perfect steady increase in Rev's upto about 3500rpm then it seems to die off.
The RPM doesn't drop... the acceleration just seems to slow right down, and then it picks its self up again. It seems to do this in every gear and always at the same kinda of RPM area. It's definately not a Miss fire because the car doesn't cough or splutter it just has a gentle sigh....like its taking an "acceleration rest!!" for a second or two and normaly when i need it the most.
The car and ECU is completely standard apart from a de-cat pipe and a Bailey Dump Valve. I've seen loads of GREAT posts on here and its given me loads of susspitions, but i just thought if i put my own symptoms on here you guys might be able to point me in the right direction.!!!

Any Idea's Guys??

Ta

Vinny

 

MAF sensor.

Get it checked out quick as the engine may be running lean and could result in serious failure. 98-00 cars used hotwire MAF's which were delicate and troublesome. Tell-tale signs are a flat spot in the power delivery and an erratic idle. As MAF's deteriorate rather than simply fail, the ECU has time to compensate and so mask the failing component. You could try an ECU reset (using connectors under steering column or disconnecting the battery for an hour) to see if it brings an error code up immediately after.

If it is the MAF, be aware that the dealer will try and sell you a complete MAF including housing, which are very expensive. A new sensor can be fitted into the existing housing, and the sensor alone is IRO 90 quid.

 

Thanks for the Quick reply!! so do u think if i do the ECU self diagnostic check, The MAF Fault code will show?? also if its running lean, wont i be able to check the plugs and look for the old White chalky Plug tip syndrome??

Is there a definate way to check the MAF sensor?? as i'd hate to fork out 90 quid for something i may not need.... lol yes.. i'll admit it.... i know ur all saying it... IM TIGHT!!

And if i do buy one.. can it be fitted or is it a garage job?? bearing in mind i am a marine engineer lol.. but i dont do much with the old electrickery!!

 

ECU reset should provoke the fault code if it is the MAF at fault, and yes you should be OK replacing it yourself if you have reasonable mechanical knowledge. If it doesn't pick up the fault though, I'd get a diagnostic done ASAP at a dealer or specialist.

 

well £76 later... and a new MAF sensor... ECU reset... the problem still remains ... seemed to be ok for a few hours after the ECU reset though There was no Fault codes on the ECU Diag either... very strange... i live nearly 70 miles from a main dealer....but i will book it in... anyone have any ideas what else it might be???? HEEEELLLPPPP lol

 

BUMP***
Fitted a boost guage on saturday to make sure i was boosting properly, getting 12 PSI with no fluctuation when i got my foot to the floor. so thats ok... and the boost doesnt drop at all when the flat spot kicks in.

Does any one have any ideas at all?? im at a loose end now ... lol.... going to Change the plugs today just in case... anyone know roughly how much a Dealer PLUG IN might cost ?? as i feel this is the only other option...

Cheers Guys!!

 

Hi mate, where abouts are you ( location wise )

 

Hi... Im in North Wales (Anglesey)... out on a Limb Im affraid!! Ordered some new plugs today so will give them a change just for piece of mind!!

Seems a little better today, I always run the beast on Shelll Optimax... but last night i put a full tank of the new V-Max Fuel 99 ron ... so not sure if thats made a bit of difference.

Any Ideas Peeps???

 

BUMP...... Anyone???? any ideas???

 

I had a similar thing and mine turned out to be a knackered coil pack...... It looked ok but thats what it was..... Might be worth looking at.!!!!!

 

im certian my plugs dont have individual coil packs, the leads just come straight from a coil unit.... i've got some HKS spark plugs on the way with a higher heat setting to see if that makes any difference. It was a suggestion from a local petrol head guy!

anyone else had any similar probs?? or solution iseas?