Hello,
I have a 2002 L100 4 cylinder that has been having what I would call a misfire for quite sometime now. I have replaced the plugs, the coil, and the icm (or ecm, the metal thing that plugs into the coil). No one of these fixes have worked. I took it to a GM dealer and they told me that would START with a cleaning of the injectors but at $425 that hardly seemed worth it for a guess.
The symptoms I have are an occasional misfire while at idle with the AC off. With the AC on and at idle the misfires are quite frequent. I cannot say the misfires do not happen while driving but if they do I do not notice them. Any ideas on what to check next?

Thanks
Nicholas

Have you tried cleaning the EGR valve? It can sometimes stay open when it's supposed to be closed during idle from carbon exhaust deposits propping open the pintle valve. Removing it and cleaning it thoroughly with a small steel wire brush on the pintle valve and seat should help. It should close completely when opened from an internal spring otherwise the electrical one's are driven by servo motors and will home when electrically connected and the engine is started.

Can you please describe to me where to find the EGR valve? I took my
car to my mechanic brother and he said it did not have an EGR valve.
He cleaned something else though and thought it was fixed but it is not.



Thanks

Nicholas

Does it look like this;


[img]uploads/ducky/egr_valve.jpg[/img]


Its located on the right side of the engine as you look in from the front of the car.

I will take a look when I get home. Thanks for the pic.

Nicholas

Well I could not find an EGR valve so I took it into Saturn and they
told me that my coil (which I just replaced) was bad. They figure I
got a bad after market coil from NAPA. I am working on returning my
coil to see if that fixes the problem.



Thanks

Nicholas

90% of the timeit's the dis module and coil. alsovery rare butseen some 2.2 motors with bad rings. do compression test. can buy at sears 50 bucks