smoke/stuttering (only at high RPM's)
 

im trying to figure out why this is happening. if it were the turbos id expect the smoke to be present any time the turbos were active... but if im just revving in neutral i still get smoke and stuttering at 6K rpm and up. it gets worse with higher RPM's. someone suggested it may be a bad coil? does this seem plausable? how can i check to see if they are bad or going, or just malfunction at higher RPM's?

do you guys have any other thoughts as to what to check as a cause for this? thanks as always :biggrin:, heath

bump
:)

anyone? im going to have the UIM off in a few days to swap out a FPD and some coolant hoses. i figure while everything is apart it would be a good time to replace any "bad" coils (if they exist). but the question is.... since the problem only surfaces at high RPM's ... how do i conduct a test to mimmic that? there must be 1000 things that could be causing this smoking/ stumbling problem.... where would one start?

what's the duty cycle of your injectors at 6k+?

What color is the smoke?
General Rule of thumb is...:
Blueish = Oil
Whiteish = Coolant/water burning
Black = Running Rich

The coils definately could be an issue if your having problems up top... Sometimes worn out/out of spec plug wires can cause missfires as well. Im sure theres information either in a Factory Service Manual to inform you of spec on the coils so you can check things out.

Normally when a coil is out of spec in relation to the shop manual its measured in the resistance.. If its within spec then chances are doing ok. I am not sure if you 3rd gen guys have seperate ignitors for the coils but if you do make sure to check the spec against those as well.

dont know... whatever the stock ECU decides