[justin99]

I was currently running ac-delco 41-932 gapped at .060 and the other day the car threw a misfire code when i was at wot. While changing the plugs i put on a front PEM and put in autolite 104's gapped at .054. The car ran ok at wot, but at idle in park and in drive the car was lopy and the rpms would jump up and down. While scanning the car that night the SES light came back on with a misfire code. Did some research and was told that maybe the 104's were too cold for my mods and to get new plug wires. So today i put in autolite 605's gapped at .056 and new wires. Did a few runs and have 0 KR, and no misfires at wot but while idleing the car was still lopy and the rpms still move. The problem started after putting on the PEM. Would that make the car lopy. And today when i did the scans there were misfires for about 1 sec in 3 different cylinders at idle when i first started loggin. After i made a few runs there were no misfires at idle but it felt like it with the rpms moving. Any ideas. I also have the TB screen removed. Can that make a difference, because the car does this while in park and neutral and drive while idleing.

 

[1Hot97]

You don't say what year or model your car is, but removing the TB screen can adversely affect the low speed running of the engine among other things.

 

[justin99]

99 gtp w/ 3.4", 9" open cone K&N, throttle body spacer, autolite 605's, front PEM, no ubend/resonator, 160 degree drilled thermostat