My W reg car has had an intermittent fault for months - engine catches and jumps, and revs go wildly up and down, often settling around 2000 when clutch in. Wonderful garage been trying for ages, replaced every chip in ecu and changed rev control valve, changed ignition coils, ht leads and plugs. Diagnostic computer brings up inaccurate fault codes or the car won't 'talk' to it at all - they're losing money trying to repair it as they can't charge me when it's not fixed. That said it's cost me nearly £800 so far, and I can't even trade it in until it's sorted. Drive fine after fixing for a day-a week, then all starts again. Any ideas???

jmh, June 2008

Thanks Caine, that's great - when I ring them tomorrow to take it in (again..) I'll take in a print out of your answer!! Any other suggestions, anyone???

jmh, June 2008

dont know if this is helpfull but i had an astra in once with similar problems,chased it down to an intermitant alternator fault.ecu and all messuring sensors work on 0-5volts to mesure vacum throttle position etc,ie .5 volts on throttle means tickover ,the alternator occasionaly went nuts outputing 18.5 volts totaly screwing up all sensor readings ie throttle closed sensor reading 4.5 volts or full throttle.wort.h a try to dissconnect alternator next time your car goes nuts.car will run without alternator long enough to test.good luck

caine, June 2008