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Random misfires........

Timing

Timing

New member
Im lost on this one. I am getting random misfires across all cylinders. I have done everything except for icm and fuel pump on this car. It seems to misfire worse when i first start it and less as it warms up. There is no check engine light and i only know its misfire due to scanning. At wot when trying to shift different gears it does it so bad at 100% load to the point the car jerks and wont shift until i let off the throttle. This started and seems to be getting worse ever since i tuned the car and disabled torque management completely. This brings me to believe fuel pump. My fuel trims are all within -3 and sometimes but rarely hit -5. Vacuum is good sitting at 20-23 idle. Ive seafoamed all cylinders multiple times. Fuel filter was changed about 6k-7k ago.
Injectors were taken off and cleaned and sprayed nicely. I did do the lim gasket and did torque the bolts correctly however i didnt think to put thread sealant on the bolts and dont really think that would cause issues after only 4k miles and my oil is perfect. It does seem to me there might be a slight leak that i cant pinpoint in my headers but can hear(possibly in my flex). Anyone have any ideas? This is driving me crazy i want to take this thing to the track the get some numbers befor winter hits.
 


Yea icm is still 120$ my cost though and thats not a gm part, its Standard. Cash customer is like 210-220
 
ebay, craigslist part outs. if you search, you will find one. someone here may have one, or be able to pick one up for you.
 


Scottydoggs said:
ebay, craigslist part outs. if you search, you will find one. someone here may have one, or be able to pick one up for you.
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Just searched advanced for the part number and the 04 has the same as 2000 supposedly. I could of swore my 2000 looked different when i had it. Ima take a look at my local pick and pull tomarrow. They have a few 3800s.
 
lol just did a car-part search for one and they all want around 75 used. Yup back pocket it is.

I used to work at advanced and didnt even know this but i heard they can test them there.
 


ICM are the same between each year there's not a 04 specific one. All else fails message me and I can probably snag one for a few bucks at the local JY.
 
REDCOMPG said:
ICM are the same between each year there's not a 04 specific one. All else fails message me and I can probably snag one for a few bucks at the local JY.
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Thanks man do you know if they are the same for the 3.1 ect

n/m answered my own question, they are different
 
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So icm replaced today and still same thing but i got another icm 3 coils and an extra strut tower brace for 15 bucks so if anyone needs one lmk.
My next move is testing fuel pump and front o2 sensor.
 
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