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Cylinder #3 misfire

F

fastlyfegtp

New member
Hey guys, I have a 2000 grand Prix gtp 2dr 150,000 miles that has a misfire detected in cylinder #3 and don't know why. When I got the car it had three Ac Delco iridium's in the back and AL p606 in the front three cylinders. I changed the plugs to AC Delco platinum rapid fires and the car started to hesitate and idle real bad and I had to give gas to start. Changed the plugs to AL 606 copper cores and it regained the power back and still has cylinder #3 misfire detected, what could it be?? The car performs like there's no misfire but the code won't go away
 


Plat. plugs blow.

Get some AL606 coppers.

Gap them at .050". Get new wires and clean the coils as well.
 
blueguy said:
Plat. plugs blow.

Get some AL606 coppers.

Gap them at .050". Get new wires and clean the coils as well.
Click to expand...

fastlyfegtp said:
Hey guys, I have a 2000 grand Prix gtp 2dr 150,000 miles that has a misfire detected in cylinder #3 and don't know why. When I got the car it had three Ac Delco iridium's in the back and AL p606 in the front three cylinders. I changed the plugs to AC Delco platinum rapid fires and the car started to hesitate and idle real bad and I had to give gas to start. Changed the plugs to AL 606 copper cores and it regained the power back and still has cylinder #3 misfire detected, what could it be?? The car performs like there's no misfire but the code won't go away
Click to expand...



Well said BlueOne
 


ITs the plat plugs.... change them

Edit: sry just read you changed them. Make sure you didnt crack the porcelain on the #3. Al are kind of cheap and crack easy. If all else fails do a compression test
 
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Coil should be fine. If the coil was bad #6 would have a miss as well. Plug wires is the first
thing id try swapping just to be sure. Then I'd do a comp test to make sure #3 is good. Then I'd try swapping injectors.
 
if your worried about the coil, swap it with another one and see if the misfire moves, or stays. ..i ended up replacing the icm under the coils for my misfire on #2 to go away.
 
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