Ba Xr6T Engine Performance Issue

[Kellar]

Hope some one can help with the following: BA 2003 XR6T Auto no modifications as far as I know, after recently purchasing vehicle replaced coil packs, plugs, fuel & air filters, lubricated boost controller, general check over - no obvious boost leaks, running 95 fuel all seem good - engine performs well, very strong - in particular when cold - EG full throttle flat out when cold - very strong, when engine heats up during a full throttle run the engine will break down anywhere from 3.5 to 5k, which feels like coil pack (that familiar thrrrrrrrrrrrrr)when this happens I obviously back off, then the engine looses all power, has no throttle response, will gradually slow down,(have driven 3 ks like this to get to a freeway exit) while lumping over, if I pull over the engine will lump over, cough, splutter & sometimes stall, weather the engine stalls or it is shutdown, restarting the engine solves the problem, runs fine - although seems a little doughy, until I boot it again - then ground hog day can anyone advise the possible cause?

[seventytwo]

My pick would be valve springs, early models had weak springs and given the age of your car I would say they are definitely on the way out

[Kellar]

Thanks for the tip, even @ 82000ks?

[seventytwo]

Yup

Do a quick forum search, there is plenty to read on the subject

[davidald]

Amazing how often there cn be trouble after changing the coil packs etc. Was there something wrong with the old ones? Check they are connected properly and not faulty.

[CCCC]

check fuel filter

[robbo k]

I cant believe u put the boot into it stone cold.... that's just asking for something to go wrong

[our06t]

I have bought a set of coils only to find one was dodgey straight out of the box , other than that double check all the coil fitments and wiring.

and yeh was the problem there before you changed these parts

another maybe big maybe is the o2 sensor ,the car runs on set program until it warms up then switches over to using the o2 sensor etc

Edited 23/01/10 09:46 AM by our06t

[Kellar]

I cant believe u put the boot into it stone cold.... that's just asking for something to go wrong

I do not boot the engine from stone cold, cold means temp gauge needle @ 1/4 op temp on this gauge for this is just below 1/2

[Kellar]

Sorry should read - I do not boot the engine from stone cold, cold means temp gauge needle @ 1/4 - full operating temp on this gauge = just below 1/2