95 Silhouette, Intermittent miss/stall then smooth HELP!!

[SJProwler]

95, 3800 with 4t60e. 177,000 miles. New MAF and EGR 15,000 miles ago, new tuneup, new filters.

Trouble started suddenly yesterday evening. Started fine, slowed to a stop light and tach started bouncing up and down and suddenly the speedo bounced a bit and engine stalled. Did not get a SES light.
(SES light comes on at initial key on before starting but does not come on when engine stalls.)
Re-started and would not idle, had to give it gas to get it to idle about 1500 or so. Put it in gear and it stalled. Re-started and held idle again at 1500 and got it in gear, got to about 40 mph shaking like a bad misfire and black smoke pouring out. Kicked down and suddenly it cleared stopped smoking and drove fine 40 miles home.

No SES Light but checked for codes when I got home, had a PRNDL switch failure. Cleared the code and went for a test drive. Did not repeat.

Today went out, started fine. Drove 7 miles to town no incidents. Went to come home, no start. Starter failed which I suspected was coming. New Starter, starts right up, runs fine. 1 mile down the road, suddenly starts bucking and missing, black smoke and stalls. Starts and dies repeatedly. Suddenly starts up, idles fine. Put in gear, drives normally for another mile. Starts bucking again, repeated attempts to start and stalls immediately. Finally will start with throttle pressed and get it to idle very roughly at 1500 or so. Get it moving, smoking bucking etc and suddenly clears up again and runs good til I get home.

Pulled codes again, still no SES but stored a p1670 Quad Driver 4 failure.

I don't think these codes are the issue but being set from trying to get engine re-started.

Could this be a bad MAF? I just replaced it 15,000 miles ago. Has a recent tuneup, new fuel/air filters has been running GREAT til yesterday. I only paid $500 for this van but it looks new and drives great usually. I really like it, plus it keeps the miles off the Avalanche. Any help would be GREATLY appreciated.

Glenn

[Greg Anderspn]

This sounds exactly like the issue I had for about a year and a half. After many trips to different shops, cam shaft sensors, new ignition module, and other stuff, finally had it get so bad it would hardly run unless I kept it at about 1500 rpm. The local Chevy dealer must have put a good guy on it and they found the wire harness that runs from the cam shaft sensor had melted the coating off of the wires where it ran by the exhaust manifold somewhere, they showed me the wire and you could see where it was shorting out.

Replaced and back in business. When it ran, it ran great, that's why I kept telling them I was losing spark. I would go hundreds of miles and then same thing. Check out that wire and the connections.

Mine is a '97.

Also all the backfiring and rough idle caused the intake gasket to start leaking.