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Intermittent Misfire cylinder #1 issues

R

rcdino1978

New member
So, I got a 98 GP GT, and it has a intermittent misfire. It seems like it only does it after I run WOT, and let the RPM's go past 4500 in 1st. It only misfires from idle-1500 rpm, when it does it. It smells like it is running pig-rich when it misfires, and I can feel the engine surging when I let off the brakes. I have run codes, and only get cylinder #1 misfire. It has done it off and on since I got the car, and now seems to be getting worse. It has new plugs, wires, coils, ran seafoam, the plugs look great, and it doesn't seem to affect the mileage. It runs great after 1500 rpm, and nevers acts like it is going to die or even sputter. I was thinking ot may be the ICM, since it has gotten progressively worse. BTW, it was doing this even before I changed all the parts out, so I have ruled out bad replacement parts. Just wanted to get an opinion from the experts before I drop 150 on a new ICM. I am going to be doing a top-swap soon, and wanna fix this first, so I don't end up with problems after the swap.
 


thanks! Maybe if i get a chance this weekend i will grab one from the local jy......is it the same part for a gtp also? in case they dont have a standard gt, i can maybe nab one of the gtp top swap car
 
Any car with the 3.8L

Bonneville
Park Ave
Riviera
Regal
Impala
Monte Carlo
Grand Poopie

You have a rather large selection.
 
SSOOOOOOO, it is not the icm. I swapped the plug wire for a new one, checked the coils(again) and pulled the plug.....no signs of fouling. It just "chugs" sometimes at an idle and smells pig-rich, the ses blinks when I idle too long, and as soon as I hit 1500 rpm, it is gone, only to come back at a stop again. SES code is only a #1 cyl misfire. Kinda ruling out the injector, since it is running rich, but the only other thing i think it could be is the crank sensor? BTW, i have run 3 diff kinds of plugs, and it does the same thing with all 3 kinds. Only seems to start doing it after I get it past 4500 in first, then it goes away after awhile. I really don't wanna take it to the dealer, since they will prob just tell me all the things I have already done and charge me for it lol.
 
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