Does it stumble hard or just a tiny slight mis kinda..Like you can just barely hear it in the exhaust and it leans when it does it? Does it come right back to normal revs and afr or take a few sec?

hmm...Whats controlling your fuel at idle? Megasquirt? I know mine kinda dips at idle every now and again..it does like split second blurps..wierd, but doesnt show any problem.. Its def. not a misfire in my case though...

Just start the car, and pull the plugs off the coilpacks one by one till the one yuo pull dosnt make a change.

Then that is your bad coil.


The switch that coil with another one and make sure the prob. moves with that coil.  other wise you have some sort of fuel injector prob. more than likly.

also check ur MAF

pimpsmurf wrote:

both CPS and CAS are brand new, and the silver types. They have roughly 100 miles on them.

The CAS is definately functional because I can read the angles w/ the cipher.

I had the same problem... one of your coil packs is going.  Try switching them around to isolate the bad one.  Then replace as necessary.

is this on the 07 crank?

If you have a bad voltage ripple then your voltage regulator blows.  Like I said, typically the most noise prone signals are the low level signals, such as mag sensors, or thermocouple outputs, where as the TPS signal should be an analog 5v signal (assuming its a 5v signal as thats pretty standard for most TPS signals).  What exactly does the TPS signal look like for you while idling?  Have access to an Oscope?  What you may want to try changing, assuming megasquirt has the control for it, is the throttle percent change input.  Typically there is a minimum throttle change value that triggers additional fueling, and you should be able to clear that up.  I know with the AEM there was a VSS based input for throttle tip-in, so I'm assuming megasquirt has something similar if you try playing with it.

Last edited by 16g-95gsx (2008-10-30 15:35:08)

Any progress on this?