1999 Grand Am, LD9 w/ egr
P0301 is the only code
Not intermittent, completely dead miss
replaced both coils
replaced injector
new acdelco plugs/ new boots
Compression test around 200psi on every cylinder
still misfiring, no changes
What am I missing? is there some quarky problem that others have found? Open to any suggestions, thanks in advance
Also tried using a whole different coil housing / ICM / Top cover from a running car with the same engine, and still had the misfire on the same cylinder
Mine did this when the cat was clogged
plug is dry when i pull it out, i'm looking at the wires coming off of #1 injector connector now to see if there is a fray or a pinch
Also struggling with an LD9 with exact issue, throwing 1 code only, P0302 #2 cylinder misfire
Seems to only miss at idle, strong & smooth under acceleration.
I've replaced: Coils, Housing, Plugs, Boots, Crank Sensor and swapped known working ICM
I also checked for a leak at the intake manifold gasket using Ether, but got no reaction.
How would I go about testing to see if the CAT is causing the issue, why would a clogged CAT only cause #2 to missfire?
Is it constantly missing or only sometime? Check to make sure you are actually getting spark. Pull the IDI cover and plugs and ground the threads on the plug and see if it sparks when cranking. Also check to make sure all injectors are firing. Could be a bad wire to an injector.
12.6 @ 114.6 MPH
