1. My sister has an 01 GC with 98,000 miles on it. A few months ago, it began having troubles starting when it was cold - she said she would have to crank it about three times (and each crank was longer than usual); the check engine light came on around the same time. After research on the internet and a trip to AutoZone to get the code/s read, I determined the problem to be the CPS (2 codes came back: CPS and misfire on cylinder 1, so I figured that the CPS was causing the misfire).

I spent a Saturday installing the new CPS, but the problems didn't seem to stop (the Check Engine light did go out, though, after I had it reset at AutoZone -- all other symptoms remain). So what I'm wondering is if I could have bought and installed a bad CPS (I REALLY HOPE NOT) or something else I haven't considered yet.

2. More recently, the transmission seems to shift a little harder than it has in the past. She says that it really is noticeable when under heavier load -- when the AC is on, etc.

Any suggestions would be really appreciated!

It is very possible you could have gotten a bad CPS and I don't trust autozones electrical parts to much, and if it was a BORG WARNER brand (I don't think AZ carries BW anyways) thats even worse.

But there are a few other possibilites as well - did you disconnect the battery when you replaced the CPS? Jeeps are very picky about this, if not that could be your problem. I would return the part and get another one (should be under warranty) and remember to disconnect the battery.