CODE: P0300 Random misfire on 1998 Chevrolet S10

I changed out spark plugs; rotor cap; rotor; wires; ignition coil; mass air flow senor; Air temperature senor; engine cooling temperature senor; map senor; replace fuel filter;
PVC; clean thottle body; check for vacuum leaks. Clear engine code and started engine. Engine starts with no problem runs a little rough not much after engine runs for about five minutes check engine light comes on. Check code same P0300 Random misfire. Now what’s the problem please help.
This 1998 GMC Chevy S-10 4.3 liter 6 cylinder 2wd

Asked by for the 1998 Chevrolet S10
It may be time for a compression test. You could have a weak cylinder causing a slight misfire at idle.
1 more answer
for a random multiple misfire you should try dropping the exhaust to see if the car runs any better cause a stopped up converter can cause random multiple misfires even make the car not run at all.