ive had a misfire and boosting problem on my car for a while

it would idle fine, when cold it was perfect, then after around half hour of driving it would have a mis at 1800 rpm and up untill 2000 rpm. and wouldnt go above 3500. took it somewhere and they changed my chip to another one, changed rotor arm, checked gaps etc everything and was still the same

then they put another ecu with another chip in whice was in the workshop and it was fine, so i thought i needed a new ecu.

got a spare one so changed the chips over (l6) put the new one in and went for a drive. fine when cold, shitty when hot.

it was getting hot where the ecu sits in the dash so took the ecu out for 10 mins and left outside to cool down. plugged it in and made my mate put it on his knee insted of in the dash.

the misfire and boosting problem has nearly gone, only happened twice on a 2 hr drive.

so my question is, could my chip be breaking down when hot, or both ecus? or do i need to somehow heatproof where the ecu sits to keep it coolish?

 

Could it be the wiring where it goes into the ecu? As having it on your mates lap will have it sitting differently than when its in its holder?

 

Very unlikely to be a heat issue, especially if two different ones are doing it.
I would start by changing things like the CTS as they are so cheap and looking for a dodgy connector, the CPS is a favourite one to play up so have a wiggle.
tabetha

 

well ive tryed wiv it hanging out and sitting in the holder and its doin the same things

its had pretty much every sensor changed exept the throttle posistion sensor to try and sort this problem out, but doesnt seem to have got any better exept when ive cooled the ecu and not had it in the dash

 

I would put the multi metre on the tps, and make sure it has no dead patches, failing that it might be easier/quicker/cheaper in the long run to get it on rollers and see what breaks down.
tabetha

 

well im gonna get another chip and see what happens, but i do want to get it on the rollers and set up propley and see if everythings right on it.

does anyone know where a localish one is to me which is reliable? i live near hampton court in surrey