Car not running right

[ssheely220]

My wife complained about the heat not working on her car so i checked the coolant level and found the coolant overflow tube had been cut by the belt and the car was low on coolant. So i added it and noticed that the cap was nasty with the dexcool sludge. So i added coolant and bled the system and the heat was still not working. I then backflushed the heater core and refilled. Temp still bouncing around and heat not working. So i decided to flush the whole system as that sludge was thick and nasty. Same thing no heat and now the car develops a bad miss( almost like a heart-beat). So i take the car to a shop and they say it is a blown headgasket( they did the exhaust in coolant tester and it came back positive). So i changed out the headgasket and now my car has heat but it still has that terrible miss(gets a little better when i pull the MAF senser). i put new plugs in it when i did the swap and i tried the coil pack off my 99 GTP to see if maybe it was damaged by water getting on it but it did not fix the problem. The car in question is a 2005 grand prix Comp G and i have a 99 grand prix that works that i can borrow parts off of to see if it fixes the problem so i dont need to throw money at parts. I am at a loss with this car. Anybody got any ideas

Thanks

Scott

[Explicit_Spade]

When you did head gaskets, did you reuse lim and SC gaskets or are they new?

[ssheely220]

i bought all new gaskets except for the SC gasket. I was told on the gen5 that i could reuse that one

[Fivefingerdeathpunch]

so its go new plugs ( what brand?), what about wires?

Are the plugs gapped right?

Maybe check the ICM ground.

[ssheely220]

autolite, yes they were gapped and ill take a look at ICM ground. No i reused the wires

[Fivefingerdeathpunch]

Also, if you think the ICM itself might be bad, some autoparts store will test those for free if you unbolt it from the car and take it to them.

I forgot to ask, but do you know which cylinder(s) are misfiring??

Any SES lights?

Knowing with cylinder it is can help you alot too.

Say its cylinder 2, but you have changed the plug, wire and coil.

Then you would swap injectors with say cyilnder 6, if the miss went to 6, then its the injector.

[ssheely220]

i took the one off my 99 and put it on the 05 and it didn't change anything so i dont think it was that

[ssheely220]

sorry i did not fully read your response. I do not know what cyl it is missing in. It is throwing a code but i do not trust it long enough to get to autozone to have the codes pulled.

[matt5112]

well since the head gaskets been touched I'd like to see a compression test.