2.4 Misfire Please Help!

11-06-2005, 09:49 AM
HI I have a 99 Pontiac Grand AM with a 2.4 auto. The engine it misfireing on # 1 & 3. I have Pull the coil cover off and put Longer Spark Plug Wires on to Diagnosis. The Spark From Tower # 2 & 4 Jump an Inch while Spark From # 1 & 3 only jump 1/4 inch. I have replaced coils, Coil housing, module, and Crank sensor. I have Swap Injectors bewteen cylinders, Checked Cam Timing, Draned all fuel and replace with new, Removed Converter to replace With new( melted from mifire but not going to put a new on until fixed), check Fuel Pressure, and compression test. What's even wierder is that If you have all 4 Plug wires on it will mis on 1 & 3 but if you remove one of the wires from the coil tower on the missing cyl. the engine will pick up the other missing cyl. The scanner also reads Misfire on 1 & 4 not 1 & 3. Also if I swap The Spark Plug Wires From 1 & 4 and 2 & 3 the skip switches to 2 & 4. That tells me it has to be a spark problem on towers 1 & 3. Has anyone ever had a problem like this. Any Ideas will greatly appreated.

11-06-2005, 03:43 PM
Welcome. It sounds like either the control module is bad or there is an issue with the ecm. Have the new control module tested, if thats ok then I would suspect the ecm is defective or there is a short in the wiring somewhere. I'm not sure if autozone or any other parts store can test the ecm for you if you bring it to them. Good luck.

Add your comment to this topic!