I have 1999 Chevy 2500 4x4 and it is misfiring on cylinders 2,4,and 6 with cylinder 4 being the most consistent misfire. So far I have put on new plugs, wires, and distributer. I am thinking it might be a computer but before I commit any more money to it I am trying to find out if anyone has any other ideas as to what it may be. The ironic thing is, is that it started misfiring only when it was cold and then once it warmed up it stopped. Then I replaced wires and plugs and now it misfires more randomly with no common pattern. I might start it up and it will run fine for 20 minutes but then stop at an intersection and then it misfires for a little bit then it will run fine.

Any ideas would be greatly appreciated.

 

I heard 98s had injector issues. possibly maybe something similar...

 

What motor do u have, what plugs did u use?