Chevrolet Repair: P0301 code Random misfire, intake manifold gasket, vacuum leak

Question
I have pulled off all the wires on the passenger side of 1996 4.3. No difference in engine idle (still idles a little ruff).  Put spark plug on all of the pulled wires and got fire on all 3 wires.  Does the PCM control the fuel injection or would this be cam sensor. Truck starts and will run, but lack of power. Can PCM be re-programmed?

Answer
I'd check the fuel pressure, and if it's up to spec, check for a vacuum leak.

EGR valve sticking is a prime vacuum leak.

Intake manifold gasket is another common one. Spray some carb cleaner around the intake manifold gasket with the engine running, to see if it makes a difference.

Van