I have a 2004 Monte Carlo SS, 3.8, 65,000 miles. The check engine light is on and is usually on steady unless I accelerate it starts flashing. The engine is ideling rough and when I accelerate it kinda bogs out and hesitates. I checked it with a timing light and it showed that the #3 and #6 cylinders are misfiring. I replaced the coil pack that those cylinders both link to but it did not help. If any one can give me any advice I would really apreciate it.

 

I'd replace the wires and the plugs. They're more likely to be the problem as the Coil Packs.

See that the wires aren't grounding themselves to the block. The Plug Caps on the Firewall side get baked and might lose continuity.
Swap the Coil Packs around and see if the misfire goes to different Holes.

Whatever it IS shouldn't be too hard to find and fix!

 

mine did this on #3 change the plugs and wires and check your plugs when you pull them those two will be black or darker then the others.

fixed mine in about 20min.
and about 50 Bandiads and a case of sodas and a bottel of suthren comfort (dont drink beer)

 

I hate to be digging up an old thread, but I ran into this problem and spent a ton of unnecessary money trying to find it. With my car, it wasn't the coil packs at all. One of them was a little rusted over, but some sanding can clean it up. I replaced it anyway with new clean ones. Anyway, the Catalytic Converter! If you have anything that can test the emissions or whatever, check it out because a clogged cat will do that along with causing an exhaust leak. New coil packs, spark plugs, catalytic converter, and exhaust pipes was too much money for me to spend on the car the week after I bought it.

 

Also check for an intake leak. Those are the typical cylinders that coolant will leak into. Besides, the good 'ol Dexcool thing again, I won't beat that dead horse. It's always worth a try. A couple of ways to check for a leak or coolant in the oil: Bottom of oil fill cap, BAD condensation and white/yellow frothy substance. Good luck and keep us updated.

 

Welcome to MCF Dustin!!! I'd also look into the cat converter. But the best thing to do is find out the the CEL is coming up with. Get a free scan at Autozone or pick up a $100 scanner and you won't have to drive there all the time.

 

I replaced the spark plugs and plug wires. The check engine light turned off and the car has been running great ever since. Thanks everyone for your advice!

 

How long did it take you to replace all the Plugs and the Wires.

The first time I tried it it took me forever to get the Original Wires off the Plugs on the Firewall Side and a whole lot of leverage to break-loose the Factory Plugs from being Installed at the build site.

All in all it took me three days to do the whole job.
Of course, I didn't know about rotating the engine forward 'til day two!

 

3 days!!! OUCH!! lol

Mine were welded on also. thanks to the whole GM idea of doing them the way tha tit was with nothign on them to keep them from sezing on there.

But it only took me under a hour to get them off and new ones installed but i had plugs and wires so i didnt care if they were to tear the wires apart.

 

man im having this same issue as well