problem: reluctant to accelerate at times..
 

Hi,

Out on a sunday afternoon blast and i've noticed my impreza wrx ( 2000 ) has started to become reluctant to go on boost at times... in fact at one point it hesitated so long i gave up and came off the throttle because it just wasnt going to go!!

Rather worrying, so whats going on?

Whats the first thing to check?

( oddly, the majority of the time it's fine, just every now and then, altho it is pretty poor at low revs at the moment, dunno why.. )

Thanks!
Dan

Hiya,

How is your car behaving at idle- is it even or uneven? Do the revs drop/car threatens to stall at junctions, but suddenly recovers?

If the answer to either of the above is yes, your MAF might be on its way out. It's a known weak spot with the 99/00MY cars.

If it is the MAF then it's not an expensive part to replace, but it needs to be done ASAP as it causes fueling issues that can lead to det, which can destroy an engine.

Get it to a specialist and until you've established what the problem is, drive it gently off boost.

NS04

It actually runs fine at idle, never threatened to stall at all, and the odd thing is that when properly on boost it drives faultlessly, it's just that initial getting it onto boost bit... So it's not _exactly_ as you've described..

Thanks!
Dan

Check all your hoses air could be escaping, even a slightly loose jubilee clip that looks like it is on okay could be the culprit. Or it could be a split hose.

On my other car, an old 87 Audi quattro it had been driving like a bag 'o' $hite with no performance. Turned out to be an injector had popped out on no.4 cylinder creating an air leak.

On the scoob though I don't think the injectors are likely to work themselves out as easily?

HTH.

Damian.

All seems basically ok, but can't say i really know what i'm looking at :)

Oddly it did the same today, coming out of work, had a right chug going on, but 60 seconds later it was fine, and was then fine all the way home. It's never done this before.... But it was never gonna stall, nothing like that, which everyone says is the maf problem?

I wonder, could it be the tesco 99 ron i put in.. Perhaps it really doesnt like it, or god forbid, perhaps they didnt clean the tanks right?? I've had this before tho, just not this bad, so im thinking it can't be that..

I've mailed xtreme to see what they can do...

So it was fine until you filled up with tesco s unleaded???

Well, it wasnt perfect. It's done this before, but i guess i could say it's got worse since then..

i'm thinking i'll get a full tank of optimax asap and do some blasts :)

Dodgy fuel pump ?

Lambda (O2 Sensor) on its way out !!! Gives sypmtons of running out of fuel, Chugging , won't excellerate Etc & then goes fine ..

Dean

Ah excellent, is this an easy job to do myself? Is there any way to actually test the sensor and confirm if thats the problem?

You can check the voltages , but to be honest they can be fine one minute & not the next or Ok for days & then it appears again, Did you say yours was a MY99 ?, The lambda screws in the Exhaust downpipe, Towards the top just behind the turbo & then has a multiplug, 3 wires. Awkward but achievable, You may loose some knuckle skin !!!

Dean

Well just been down to xtreme, and they sorted it. New Maf sensor, and couple of other bits.


the thing is amazing now, i just can't believe the difference, it feels like it has 50bhp more at least! 2nd gear acceleration is back to being obscene :) I thought i was just getting used to the car, but no, it had been the car slowing down all along! DOH!