It looks like you're new here. If you want to get involved, click one of these buttons!
Meet your fellow owners in our Owners Clubs
See Official Rules for eligibility and other requirements.
GMC Envoy Cylinder Misfire
I have a 2005 Envoy 4.2 I6. About 2 years ago we had the ECM replaced with our extended warranty because it was throwing codes. Just recently it started to throw codes. I hooked the computer up to it, and it is reading P0305-cylinder 5 misfire. I replaced all the spark plugs with Bosch Platinum 4's and cleared the codes. The same day, it threw the same code. So I got a new coil and replaced the one in cylinder 5. Again, cleared the code and came back. Took the new coil and moved it to a different cylinder to see if it was the coil and still getting the same code. I have tested the battery, which is sitting within normal range. Hooked a ground wire from the ECU to a different ground to make sure that there was an adequate ground and got nothing. I have looked at the graph on the computer while the car is running and all injectors are pushing the same amount of fuel through them. I am at a loss of what to do. Can anyone help steer me in the right direction?