So I took my Camaro to get it inspected and it was throwing an P0300 code. The service engine soon light is off and the engine runs really well, without hesitating or stumbling. I cleared the code a few days ago, put about 30 miles on it, checked it, and the P0300 was being thrown again. What could be causing this? My plugs are clean and my wires are new (in fact, they're Accel 8.8s). Unless it's my Opti, I don't know what the problem could be.

 

The SES light should flash when there is a misfire. Does it?

 

Sorry, I didn't mean to abandon the thread. Anyway, the light isn't working at the moment, I have a grounding issue. The misfire is intermittent, as I can check the codes on my scanner and nothing comes back until the engine starts to get to 210.

 

Does your scanner cover "GM Enhanced Parameters"? If so, you can pull up the misfire count by individual cylinder.

 

Sadly it doesn't. However, I found out that my MAF plug was cracked and was loose in the connector. The P0300 has gone away but it's become a P0302.

The injectors all ohm out to around 13 ohms and fire consistently. They're not new, but they don't leak and seem to work. I haven't checked my Opti or coil yet. Could these be at fault?

 

If you had an injector electrical fault, there would be a code. The fact they are pulsing does not prove absolutely that they are functioning correctly. A plugged injector, or an injector stuck open would not exhibit electrical issues, but could cause a misfire. Swap the #2 injector with one of the others, and see if the problem follows the injector.

A problem with the Opti, the coil or the ICM would generally affect all cylinders. The exception could be a burned contact on one cylinder in the Opti cap, but that would seem to be less likely than a wire or plug problem. I would also check the plug wire terminals in the Opti for corrosion.