Still have a miss (frown)

[19b]

'91 s13, race car, dirt track, 120,000 miles. Had an intermitten miss, found a plug wire with erratic resistance, replaced all. Took it a little while to fire completely, carboned up? Ran well....... next week, .....next race, it didn't want to fire, then did, now won't. It seems to fire well up over 4500 rpm once it gets cleaned out, but if it dips below 4500 or so, the miss is back for a while. She races a whole lot better when all 4 are happy, obviously. Thanks

[NISTECH]

is the miss only on one cyl, can you isolate it to which cyl it might be? You may have an injector leaking and fouling it.

[19b]

Thanks, sounds like it. Will try.