Hello Nation,
I have an '07 Envoy SLT 4WD with about 103k on it. A few months back I went on a quick trip to the store. On the way back, I kicked it down to pass somebody and I felt the truck stumble. When I got off the freeway, it had a little roughness to it and died with a violent shake at the light. I got it started, and it reluctantly ran - I had to shift into neutral and rev the engine to keep it from stalling again, easy to do in a stick but not so much in an automatic. Got it home and gave it a once over. I get P0300 - Random Misfire. Cleaned the TB, changed the plugs and even swapped some coils - no change. Hard start, rough idle for a few seconds and then stall. Last thing I did was a compression test. 210 in cylinders 1 through 5 and zip in no. 6. Found out that it could be a burnt valve so I dismantled the engine to remove the head and that is where I am stuck. I got the engine to TDC using an alternative method that Eric the Car Guy used - I didn't feel to good about sticking a screwdriver in the cylinder. I look at the timing marks, they are in the right place but the dark links on the timing chain are not. In fact they are three links advanced. My question is: how did this happen? I have had the vehicle since 2010 and have not performed any maintenance other than what is necessary/recommended. I have trouble thinking that it would have been put on incorrectly at the dealership had it been replaced, I know the timing chain can jump but what causes it and should I be concerned about internal damage?
I have an '07 Envoy SLT 4WD with about 103k on it. A few months back I went on a quick trip to the store. On the way back, I kicked it down to pass somebody and I felt the truck stumble. When I got off the freeway, it had a little roughness to it and died with a violent shake at the light. I got it started, and it reluctantly ran - I had to shift into neutral and rev the engine to keep it from stalling again, easy to do in a stick but not so much in an automatic. Got it home and gave it a once over. I get P0300 - Random Misfire. Cleaned the TB, changed the plugs and even swapped some coils - no change. Hard start, rough idle for a few seconds and then stall. Last thing I did was a compression test. 210 in cylinders 1 through 5 and zip in no. 6. Found out that it could be a burnt valve so I dismantled the engine to remove the head and that is where I am stuck. I got the engine to TDC using an alternative method that Eric the Car Guy used - I didn't feel to good about sticking a screwdriver in the cylinder. I look at the timing marks, they are in the right place but the dark links on the timing chain are not. In fact they are three links advanced. My question is: how did this happen? I have had the vehicle since 2010 and have not performed any maintenance other than what is necessary/recommended. I have trouble thinking that it would have been put on incorrectly at the dealership had it been replaced, I know the timing chain can jump but what causes it and should I be concerned about internal damage?