Cliff Cox Posted November 20, 2010 Report Share Posted November 20, 2010 I have a 93 Seville sts 4.6 northstar. It has a misfire/ rough idle.... I have owned it for about a yr. 145xxx miles. Daily driver up in till 3 months ago, then it has been sitting. Also have a Chevy van sat longer with no problems, it runs perfect even after sitting. Same gas (93 octane) in both vehicles. This all started after it sat for a few months, now I wanna start driving it again. I have changed the plugs, wires, air filter, & found no vacuum leaks... The rough running goes away at about 2200 rpms. It runs fine until it is idling or cruising at or under 2200 rpms I was thinking next to clean TB & MAS... Any other ideas/ suggestions????? Link to comment Share on other sites More sharing options...
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