99 Suburban: Engine Misses Then Quits While Driving

[mneder]

1998 1500 SLT 4x4. Bought used with 86K miles. Drove fine until 100K miles. Then, while passing a car on the highway the car lost power and then the engine died. The gas tank was full. Engine wouldn't re-start. Called mechanic who put in new battery. Engine started OK. Started driving back to town and engine again started missing, bucking and knocking. Pulled over, stopped engine and towed it back to town. Diagonosed as engine failure. Replaced engine with new NAPA engine.

At 105K miles while cruising on highway, the engine seemed to miss once or twice during the space of a few seconds. Then fine until 50 miles later, when the engine acted as it did the first time. Missing, loss of power and then quit while driving at highway speed. Gas tank almost full. Engine would re-start and idle normally, but bucked and died when attempting to drive it. Called wrecker and towed into town. Dealer checked fuel pressure (OK) but found some wiring (timing/ignition?) that was out of place, chaffed and rubbing (grounding out) on the engine block. There was also a timing computer error. They repaired and re-routed the wiring and the car drove normally.

Yesterday, at 106K miles, my wife was returning from a weekend trip of about 4 hours driving time. Just before reaching the house the engine missed and then quite while driving at city speed. She pulled over, re-started the car and drove home. Gas tank half full. She told me about the problem. I went out, started the car, and noticed a slight hesitation (miss) which then went away.

I'm at the point where I don't trust the car and, because of the intermittent nature of the problem, I am less than confident in a shop being able to identify the problem.

Suggestions, please. All opinions/questions appreciated.

[surfburb]

Was your fuel pump ever checked?

[mneder]

Originally Posted by surfburb

Was your fuel pump ever checked?

The second occurance they checked fuel pressure and it was OK. But who knows. This problem is intermittent.

[mneder]

With all of the experience on this board, I'm really hoping for some good guidance. Please help.

With the intermittent nature of this problem, I am going to have to start replacing components that appear to be good.

Where do I start. Fuel system? Electrical system? Which components do I replace first, next, last?

TIA-

[95silverado]

There have been some problems with crankshaft positiion sensors. The ecm uses information from the crank sensor for timing. Since the ecm has set a code for a timing error the crank sensor and it's wiring would probably be a good place to start. I hope this helps. Intermittent problems are the worst.

[mneder]

Thanks, 95Silverado.

Here's one more clue. I looked at the receipt for the dealer shop visit after the second occurance. They noted Error Code P0339 on the ticket. That's when they found the wires shorted to the exhaust manifold. They also replaced the fuel filter.

[95silverado]

Code P0339 is "Crankshaft position sensor A circuit Intermittent" Maybe the sensor was damaged when the wires shorted to the manifold. Anyway here is a link to a list of OBD II codes.
www.troublecodes.net/OBD2/pcodes.shtml

[mneder]

Thanks, again 95Silverado. Sounds like this is a logical place to begin replacing components. Is the sensor difficult/expensive to replace?

[95silverado]

The part list for about $89.00 from GM. Not sure how difficult to replace.