2005 Chevrolet Colorado Repair Question
Trouble code p0304
Did you try swapping the plug with another cylinder too?
Take a compression test also.
first of all, you missed the obvious. try changing the spark plug and I bet your issue with the 304 is gone
if you disconnected the pcm, you now have to have the pcm re flashed or re programmed. you ereased the memory in the pcm.
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You shouldn't have any programming problems with the PCM. It will lose the adaptive memory and any codes stored but that should be all.
Changed the spark plugs with the new coil with no improvement. Compression is good. Did not disconnect the PCM - just detached it from the firewall (plastic fingers).
If the spark is good, compression is good, that only leaves the fuel injector. You can try moving that injector to a different cylinder to see if the misfire moves with it.
Thought about the injector too. I was probably not clear. I changed the spark plugs but still have no spark out of four. I put a plug in the coil out of the cylinder to check that. Checked all the voltages on the plug but not sure if I am seeing pulses on the green wire. That is the wire that goes back to the PCM. With all the other issues (door locks, driver's window, and radio) I am still wondering about the plug going into the PCM.
If you have power and pulse to the coil, you should have spark if the coil is good, assuming you are grounding the spark plug or using a spark tester which is what you should be doing.
I know I have power and ground but I am not sure if I have pulse to coil. Any down and dirty way to test that?