Smitters

The problem is this:

When my engine is warm, if I put the car under load, eg. accelerate more than gently, or am driving up an incline, there is a sharp cut out of the engine. The only way I can describe it is as though you've gone round a corner with a really low level of fuel and there's been starvation briefly. However, this is a continuous cut out, run, cut out, run, so the car bounces a bit down the road.

Also, if I put my foot right down, there is nowhere near the sort of gain in speed I would expect, plus it still stutters. The stuttering occurs from not too far above idle, and definitely occurs by 2500rpm, though it continues all the way up the rev range.

I have had it to the local Subaru garage, who diagnosed needing new leads, which I have now added, but to no avail. They reset the ECU, but the problem gradually resurfaced and gets worse by the mile. It had new plugs at the last service (May-ish).

It's a 1999 Impreza Turbo 2000 (so the WRX wagon). Edit - no mods, other than a backbox.

Any ideas? I should add I'm not mechanically inclined, but if needed I can post a photo of the engine bay for people to point things out on!

Many thanks.

Smitters

Turns out to be a dodgy MAF (shocker!) and also a cracked spark plug. I'd discounted plugs since they were brand new 2000k ago. Just goes to show. Even the garage that did the service and mucked up the plug didn't check them. Cue one (polite) complaint and one lost customer.

£500 on diagnostics, a set of unnecessary HT leads, one of which is now a bit knackered due to arcing and two months of decent driving conditions lost. Boo. However, thanks to Powerstation for taking all of 1 1/2 hours to find, and fix the problem.

The lesson. Never overlook the obvious, I suppose.