Misfiring HELP!!!!

**Grandprix07gt** · 12-23-2010

hello all im new to this tread and I was having problems with my grand prix misfiring. I recently replaced the pcv valve, spark plugs, wires and cleaned the throttle body i Keep hearing that it could be my coils i just want to get other options before i decide to replace them. When I start the car its turns on quick but shakes while idle when i give it boost like getting on the highway is when it begins to misfire mainly between 50-60

some one please help
thanx oh and by the way its an 07 3.8l sc

**matt5112** · 12-23-2010

please post in the correct section next time.

**TheOtherNick** · 12-23-2010

What cylinders is it missing on?

**FordMan77** · 12-23-2010

Get it scanned for codes. That may tell you which cylinders are missing. Also, check to be sure you didn't cross any wires when you replaced them. I know it sounds dumb, but its any easy thing to check.

Jay

**Grandprix07gt** · 12-31-2010

ok when i got it scanned it read P0300 which is a multiple or random misfire.i also checked the wires and they look as to be in the correct order thanx

**RideMr2** · 12-31-2010

I am having this same issue, code P0300, on my 2007 GT.

The dealership replaced the entire supercharger assembly, rocks at idle noise.(warranty)

They also replaced the cat converter for code P0300, but this did not fix the problem.(warranty)

My check engine light starts to flash when the boost gauge(DIC) is about half way.
Back off the throttle and it runs fine again.

My plugs and wires are ac/delco professional, changed maybe 2 months ago.

I do have MSD coils, I am putting my stock coils back on today to see if that does anything.

**01gpgt01** · 12-31-2010

MSD coils suck. But I doubt its causing a random. Id look at the ICM

**Mitchstrp** · 12-31-2010

happened to me, my tuned pcm was bad. did you recently get a canned tune?

**RideMr2** · 12-31-2010

Stock coils back on, this problem is fixed.

Suggest OP replace coils.

**Grandprix07gt** · 01-01-2011

My engine is stock as of now but I'll try the coils and we can go from there and I'll check the ICM

**offroadfury6** · 02-02-2011

any luck OP?

http://www.grandprixforums.net/servi...oon-41762.html

**Grandprix07gt** · 02-18-2011

no, no luck yet. i checked the coils checked my icm replaced wires and plugs replaced pcv , i cleaned throttle body still no luck gotta check ijectors that would probably by my last option. but the thing is im not getting an check engine light anymore but it still misfires andAT TIMES CAR RUNS VERY SLUGGISH. and rides rough on take off.

BTW sorry it took so long to reply

**offroadfury6** · 02-21-2011

still haggling mine too...

**Grandprix07gt** · 03-07-2011

well i purchased the injector cleaning tool from snap on and i feel it really cleaned my system. car is running a whole lot better havent had problems since (cross my finger) try that a local shop might be able to do it for ive heard $100 but you might find a better deal good look keep me updated

Thread: Misfiring HELP!!!!

Thread Tools

Display

Hybrid View

Similar Threads

misfiring

Misfiring

Misfiring

need help!! misfiring???

Misfiring?

Bookmarks