Hello, my vehicle is having issues. It threw a po300 code. Brought it into a local shop that I have dealt with for years and they ran diagnostics and came up with that code. After the diagnostic, I was told that the only thing that would cause it was the timing chain since all the electronics checked out. Previously I replaced the plugs,wires cap,rotor,fuel filter,air filter.
I had a friend replace the timing chain who is a retired gm mechanic.(He is not up to date on the computer stuff, but understands them somewhat).It does it most when you are driving on a flat surface or going down a slight incline when the engine isn’t under load. It uns extremely bad when it is raining or damp outside. I also ran two tanks of fuel with Seafoam in them.It was doing this before replacing the parts listed.(Also replaced the camshaft position sensor).
I am not one who likes throwing parts at it. Could not find any vacuum leaks. It starts fine and seems to idle fine. I am at a loss of what else it could be. I’ve even looked at it in pitch black to see if I see any arcing and squirted some water around to see if it starts running rough to no avail. It has the vortech 4.3 V6 w/csefi. Thanks for your time.
That code is for multiple misfire issues, like spark plug wires etc. etc. so I would still be suspect of them. if you did not have this issue prior to the timing chain replacement…I would be highly suspect of a problem with its installation.
Would be nice to have a qualified dealership mechanic at least diagnose this problem, anyone can repair it once you know for sure what the problem is. Might be worth a $100 check out charge at your dealership before you spend more money on this.
Sorry wish I could be more of assistance to you, but need more information to go farther.
Category: Check Engine Lights