random misfire code p0300
my 96 blazer has a random misfire code that i am having trouble diagnosing. i have checked various possible causes such as the spark plugs distributor cap fuel pressure, sprayed brakeleen around the intake manifold, and tested for spark at cylinder 1. when i unplugged the wire at the cylinder the engine seemed to run a little better. the main problem is cant seem to let the engine idle because once the rpms get any lower than 650 or so it stalls and shuts off. the ignition module and coil have been changed recently, and the previous owner states that he has changed the cap and rotor along with the plugs already. but i am unsure of his rliability and have been advised to just go buy a new set anyway. i am on my way to purchase those parts, howver assuming that changing them does nothing what's everyone else think? the problem is grinding up my flywheel and burnin out starters because of the engine buckin around at start up.
p.s. the ggas pedal has to be held down for the engine to fire up. otherwise you just get backfire and what sounds kind of like detonation.