awhite4557

I have a 2006 chev silverado 4x4 PU with a 5.3 engine. The engine was running fine and then a lifter started to rattle. We discovered that the cam went flat. The engine has 175,000 miles. We replaced the cam and lifters and after getting it back together, we started it up and there was a miss that was not there before changing the cam. The miss went away and then after driving it a couple of days it started missing again.

The computer showed P0305 cylinder # 5 misfire and P0200 Injector Curcuit Malfunction. We had already replaced the plugs so we swapped plug wires between two cylinders and the codes stayed the same, the misfire did not move to the other cylinder. We then checked the injector with a stethoscope and #5 injector was not hitting properly. We replaced the injector and it now sounds like the other injectors and is hitting steady. We cleared the codes and after driving a short distance they returned again.

We swapped the coil packs for 3 & 5, cleared the codes and then drove it. The codes returned for cylinder #5 and did not move to the other cylinder.

I can clear the codes and it will run smooth and then after driving for a short distance the codes return. Now there is a P0200, P0305 and P0420 Catalyst System Efficiency Below Threashhold Bank 1. We had the cats checks by a muffler shop and they are within specs.

I was told to replace the wiring for the injectors by obtaining the needed part of the harness for the injectos and soldering it into the wiring harness on the engine. Are there any suggestions, I don't want to just start changing parts out. Any info would be appreciated.

Old Geezer

iTrader: (3)

Take a look at the porcelan on the plug[s]. U may see tracking on it, causing a misfire.
Also, are the plugs new?
The cat problem may be the ft vs rear O2 readings are not right..Original O2's?
How did the muff shop determine the cats were in spec?
A data log would help see what's going on...