Just joined and the reason is because of one of my coils. I've got 122K on a 00 SS and it's being fixed on Thursday. Just glad it was a small fix and nothing major. My Monte has never given me a problem and she still looks brand new.
I'll be having the plugs and wires replaced while their at it.

 

OK need some help here people. I replaced one of my coils that the computer said was bad, I also replaced Ign. module for that coil. I still have the same problem. When under easy acceleration everything is fine. But when getting on the freeway or the engine shifting down to it's passing gear, I get up to 4500 rpms and the engine just dies and won't accelerate any more. I can hear the engine knocking and the car actually starts slowing down. If I let up on the gas the engine will shift up and I'll gain speed. I've dropped $600 and haven't been able to fix it. I don't want to spend anymore money unless I know what the hell is going on. The diagnostic machine has said everytime that it's the coil/ign. pack because I'm getting 500+ misfires on that cylinder and my mileage has dropped from 26 to 19 mpg.
What is the deal????

 

i had this problem and it was the CAT

 

might sound stupid, but have you checked that particular plug and wire (for whatever cylinder this may be)?

 

My guess also is the cat, but with that many miles, and the misfires, change the plug wires.Check the plugs.
Wayne
http://www.cardomain.com/ride/2319272

 

I agree with rocknss04. I had similar problems with my Cat too. I was driving back home to Chicago from St. louis, and my car would go past 60 mph. I alsohad the knocking symptoms too. I thought it was the trans taking a dump, buy luckily it was the cat.
Hope this helps... MIke.

 

great info.thanks
dominic

 

Yea i had same problem with my new 05 SS i heard bit of clunkin thought it was cat. but no evryone said change spark plugs and wires. AND ILL TELL YOu 3.8 is not FUN. I didnt rolll the motor as some people said to do. but i managed. But wasnt easy. did that and it didnt fix my problem hook it up to scanner seen that miss fire at 2 and 5 soo thought it was coil pack and it was. My car also had seem to be rev limiter. coulnd go past 4k rpm

 

4k driving? or in park?

 

my 03 monte ss is doing the same thing and I was told its the cat because when its in park or neutral and you rev the engine it has no sounds or feel of misfire at all but when cruising and kick down throttle to pass it revs up fine but just seems to coast along. They say its back pressure caused by a broken and plugged cat. Also sometimes when turning from a stop its a little hesitant at first but does not give the feeling of stalling just lack of power.