2001 Chevrolet S10 Q&A
2001 Chevrolet S10 Question: Need help with code p0303.
Since # 3 is the hardest plug to replace you may have cracked the porcelain insulator, best check it to see! Center cylinder on drivers side, the one behind the steering shaft. If you changed them then you know which one it is. Go ahead and replace the dist. cap and rotor too. - pushrod
The V-6 and V-8 motors in the late 90's and early 2K's had injector issues. There is an updated injector "spider" assembly for them. Rec. you look into that, and also, (not that this would give you a single cylinder missfire) remove the EGR valve and see if there is a chunk of carbon holding it open. EGR sticking open was a big problem on those 4.3L engines. - ChevyASE
have a bore scope of the inside of the cylinder.i found out after i had a misfire and the engine blew up that the number 1 cylinder piston was completely gone and had to replace the engine - kahre