I just purchased a 2000 Impala LS (3800 Series II). Upon driving it much today thru my routine daily driving 3 (THREE) times accelerating from a light the engine coughed or stumbled making me think the engine was about to die, it did not, kicked and went on just fine. Engine idles beautifully, I've cleaned the TB and IAC. No CEL displays and most of the time runs beautifully but in nearly 70 miles of city driving today it worked great except those 3 times the engine randomly stumbled, kicked, coughed and then went on fine....... Ideas anyone??

how old are the plugs and wires? check fuel pressure? i would check the tps with a meter and see if the output is unstable.


https://www.gmforum.com/trouble-shoo...sensor-279319/

Just bought the car, so I don't know how old plugs and wires are. IF there was a TPS would there not be a consistent problem? I drove it 50 miles yesterday and it only did it 3 times....all the other times I performed flawlessly?

There are tranny codes that will set and not put the CE light on...have it scanned.....

Private party, used car lot, or dealership? Any warranty?

seems to me like something is fading out, isnt quite bad enough to set a light yet. like tps or maf. you can clean the maf see what it looks like. they are both alot easier to test if you have a live data scanner hooked up when it does it you can see what flakes out

Finally showed a "Pending" (not yet lit) Check Engine code of P0502--- Intermittent Vehicle Speed Sensor..... in researching this it stated, "symptoms of a faulty speed sensor may also result symptoms of other common components such as a defective coil pack or bad throttle position sensor."............ gonna replace this tonight and we'll see what happens.

Replace what tonight?

They are talking about replacing the Vehicle Speed Sensor.

Ok, the way he was talking, it sounded like he was going to replace the coil pack or something.

So you got the pending code for the TPS ? Could also be the IAC. Could also be your fuel filter. Those are guesses After the car stalls will it start right up? What does your coolant look like...... any oil in the coolant , any coolant in the oil? I know u said you replaced the upper intake gasket. Did you replace the throttle body to manifold gasket. I have heard of people using 2 gaskets. Also the EGR port can eventually burn a hole in the manifold.