Hey Folks, this one has me baffled. My 86 with a 22re has this miss/studder at idle and at partial throttle. I've verified TPS/Air flow meter/resistance are good. New O2 sensor. Complete swap out of ignition system. (coil/ignitor/dist./wires/plugs/dist. pickup). Now here's the really strange thing.... I turn on the AC (which kicks up the idle via a metered vacuum leak)and the miss goes away. The engine runs perfect as long as the AC is turned on. The second I turn off the AC, the misfire/studder comes right back. <img src="/forums/images/graemlins/confused.gif" alt="" /> <img src="/forums/images/graemlins/confused.gif" alt="" /> Any help would be greatly appreciated.