I have a 99 suburban C 1500 w/5.7L and 2WD. I have 150,000 miles on the car. The engine was replaced with a remanufacted one 10,000 miles ago and tranny rebuilt 20,000 miles ago. I am having a problem with the truck shutting off while at highway speed and while sitting still both in park and in drive. The tach will elevate a few hundred rpms and the gas needle shakes back and forth whiole the car is at idle or being driven. I have replaced the fuel pump, fuel pressure regulator, fuel filter, cleaned the injectors, replaced all plugs, wires, coil, distributor cap, and rotor. No one seems to be able to diagnose the problem as it isn, t throwing any codes to the pcm. My thoughts were that the fuel level sending unit may have a short causing the needle fluctuation but as far as the dead stall I am at a loss. Had both transmission specialist check tranny and was ok. Mechanic unable to find fault with the engine with the pcm module. Any ideas would be greatly appreciated.
Hummm I have seen this problem a lot of times. Check you grounds from the battery to the frame, from the battery to the engine and from the engine to the fire wall. Remove and clean them until both surfaces are shiny.
In all cases go back to basics with voltage and grounds being the most important. There is also a slug of wires on the engine block. They feed the computer and dash. Clean them also.
May, 11, 2006 AT 11:11 AM
Check your crankshaft positioning sensor. They are known to be bad, at least in the Tahoes of the same year. I had similar problems, changed everything you did, and it came down to an $80 part.
Mine threw the code once, but a mechanic said that wouldn't cause the stalling. Needless to say, I'll never go back to him. Funny thing is that the code didn't come back up. I'd reset every 2-3 months because I was getting some catalytic conv. Code. This went on for like a year and I continued to have the stalling problems until it came back up and then changed the part.