Misfiree 7 and 2 cylinders

SOURCE: 1998 Cavalier No Spark in cylinders 1 & 4

ignition mod. grounds,pcm or timing belt could all be it but, I would have to look at timing first.

SOURCE: 2003 Chevy Venture misfiring

The injector is a good possibility, although you should check for spark in the wire first, as the electrical is the weakest link in the system. Put a spare plug in the end of the wire with the plug resting on metal, then have someone crank the van to see if you have spark that far, test and replace spark plug, (do not get shocked!) then look into a new injector or a good cleaning.

SOURCE: 2000 CHevy Silverado misfire code

try also the knock sensor..computer cant adjust timing

SOURCE: random misfire

Intake manifold gasket or cracked intake manifold will cause a variety of problems including rough idle and random misfire. You can try spraying a little carb cleaner at various points around the intake manifold while the engine is idling and see if the RPMs pick up at any point. This would indicate that it is drawing air in someplace where it shouldn't. The slow acceleration is probably because the computer has set itself all out of wack and is trying to compensate, that's why you get codes like O2 sensor when it really isn't bad, it's just raw gas getting to it.

SOURCE: 5.3 L Missing and Rough Idle Intermittently

i have a 2001 chevy z-71 5.3L. I keep getting a random/multiple misfire code for cylinder 1 . I have replaced plugs, wires, coil pack(only on #1 cylinder)., and fuel pump. I still keep getting the cylinder 1 misfire code. I put truck on a scanner and watched the cylinders. # 1 misfires at idle but quickly stops misfiring at around 1000 rpms. you can here the engine miss at idle but truck runs great on road . anyone else ever had this problem?