stutters in delivery of power under load - suggestions?

[cristyn]

Under hard load there is a stutter and then the power surges through. If I go gradual through the revs all fine, and seems to happen at certain rev levels eg 3000. Local independent garage ran a check and the fault came up as the exhaust sensor temp probe wasnt working properly and therefore had an issue relaying to the Lambda (?). Changed this and the engine runs far better - but there is still the load problem. Kind of a stutter and then it's as if the circuit kicks in and then works fine? help - very annoying. it also feels like the idling or ticking over isnt smooth either - could it be as simple/old school as the sparks and leads and so not always firing quite right?
I live southeast london so if anyone can recommend a garage to go to with more S/RS experience I'd be grateful. Cheers

[spurtle]

Did you change the EGT sensor or the lambda (and one bank, or both) ?

Could be a fuel trim problem; try finding someone on here (or an independent garage) with VAG-COM and get them to reset DTCs, which also resets fuel trims. If the problem goes away but comes back after a hundred miles or so then most likely a lambda problem. They don't always throw a fault code.

I've had similar problems on my S4 (lambdas) and on an A6 (after lots of investigation, turned out to be the PCV valve).

[cristyn]

Thanks - I 'll give the garage a call - we didnt touch the Lambdas - just the exhaust temp probe etc I think, and I will continue my investigation. Cheers

[quattronutter]

pressure test it before you go any further