03 MCS with 117k miles.
Volt catback, K&N CAI are my only engine mods on this one.

I drive the 06 MCS and it jumps out of each gear (She's stock except for the K&N CAI). It just WANTS to go fast.
My 03 acts like my old 02 MC did. It takes a lot of RPMs to get her up to speed.
The 03 MCS is quicker than the MC but no where near as jumpy as the 06 MCS.

I thought it was the BPV so I changed it out. No change.

Open for suggestions..........and help.

 

The 06 MCS has shorter first and second gears. So this may explain some of it.

Have you replaced the S/C belt? This can slip and really cut down on the power.

 

I recently had a new serpentine belt put on just because the mechanic was in there anyway replacing the AC compressor.

 

Revs to speed is a fixed mechanical thing, so aside from the gearbox that's not going to change.

What's the weather like? Heat is not a friend, esp if you haven't cleaned the IC out lately and it's developed a coat of oil. How do your spark plugs look? Have the wires and/or coil pack shown signs of corrosion? Is the SC making any rattle noise (it's in the window where the gears in the SC could be grinding down if the oil leaked out). Those would be the first standard maintenance things I'd check.

 

Weather? Hot as blazes but this is not my first summer with her. I have not cleaned out the IC. Can you lead me via a thread link on that? Plugs are ok as they are under 50k. No corrosion around the plugs or coil pack. Does the coil pack tend to die?
I'll double check the SC rattle as there is a mysterious oil leak I'm chasing. I thought the leak was a dead belt tensioner but now you have me wondering if my SC is getting ready to die as I'm not losing engine oil.

 

Heat and humidity is going to make things drag more, so it may just be more pronounced with the gears.

I'd take a close look at that SC, if you can see dried oil on it I'd be careful. If you do a search Octane Guy posted a video of what it sounds like right before it's gone. They tend to leak a little dry out, grind the gears and need replacement/rebuild.

There's a common arching and corrosion issue with the wires on the posts of the OEM coil pack, #3 and #4 (rear posts) seem to be the more often culprit, many don't find evidence until their getting codes, but I checked mine and had to do a lot of cleaning.

Here's some links for IC cleaning, I remove it and spray about a total 3/4 a can of carb and choke cleaner and allow it to drain out into a 5 gal bucket. I do it about once every spring and once at the tail end of the fall.


https://www.northamericanmotoring.co...tercooler.html

https://www.northamericanmotoring.co...tercooler.html

https://www.northamericanmotoring.co...tercooler.html

https://www.northamericanmotoring.co...ggestions.html

 

I would also try to find a 02 to 04 MCS just to compare with instead of a 05 or 06.

 

Drew,
I'm on it. Thanks for the help. I'll share with everyone if I come up with something.