im getting a hesitation upon acceleration on my 97 1500 4.3 . it happens under normal acceleration but not when i accelerate hard. recently replaced alternator and problem started after that. getting a p300 code random engine misfire. is this fuel or electrical? any clues?

Make sure you have good grounds, check alternator out put, can you feel an actual miss in the engine like a plug or wire?

grounds to bat. and block are good getting 14 .12 from alt. yes can feel hesitation not misfire no skip more like fuel cut out

You probaly should have it scanned and look for pproper o2 sensor activity, look at fuel trims to see if it is running lean/rich. If it is maf equipeed this could need cleaning, look at baro sensor readings make sure they coincide with your area.

Also check for vacuum leaks - bad grommets, cracked hoses, hoses to sensors, etc. - Had a '96 Lumina with 'random engine misfire' codes and found 1) a crumbled manifold gromet and 2) a leaking hose going to the MAP sensor. Might also check the high voltage plug wires, rotors, plugs to make there in good shape, not shorted, etc.