If the cause is eliminated the ECM will most probably clear the codes by itself

 

I think with a 98, you should clear the codes, ,and if they don't return you are good to go.

 

A month after i put the accel dist cap and rotor on it started running like crap again, and now its missing so bad it wont hardly run......starts awesome, idles great gets ready to shift to second it starts missing so bad..........
two weeks ago it started i let it warm up ran great no issues, now it doesnt matter if its cold or wet out, but seems to me it ran better when it was real cold out........
i didnt remove the screen in the bottom of the dizzy cause i need the van, now i am going for a new dist. and if the screen is in the bottom of the new one not reman it will get removed.........

the cheap cap i put on it ran for three months before........ this one one month and its a performance cap with life time warranty.........
could i have maybe got a defective cap.........

sorry for asking questions yet again..........

i hate to but i will be selling it off in feb, i love it to death! its fully loaded but i dont need a 7 passenger any more and the miss's hates driving it.......
need to have it fixed so i can sell it off......

 

Is it still throwing a misfire code?

The injectors on these are known to gum up a bit. GM has a TSB on it, but I don't have it handy. Basically it says to run a bottle of GM Fuel System Treatment Plus through it. Heavy duty fuel injector cleaner basically, not cheap, but it cleared up the problem when Green had a similar problem.

If that doesn't clear it up get an ACDelco/Delphi cap and rotor in it, they just seem to work the best in these vans.

Also, have you inspected the gear on the distributor? I've seen a couple really worn ones.