No, I'm not asking how to fix this...I'm telling you what fixed it for me.
A while back I posted asking how to improve my shifting because my 1-2 shifts were absolutely TERRIBLE. Everyone told me, "Oh it's normal...you'll get used to driving a 5 speed soon enough."
Well, I shrugged it off...but 8 months later, I STILL couldn't shift worth a crap between first and second. I blamed it on me just absolutely sucking...and left it at that. However...I think I found out the culprit...unless I just suddenly got good for a day.
Last night while driving home from work around 11pm, I was accelerating in 4th gear and suddenly my Jeep bucked twice real hard like it was trying to stall out...then it was normal except my CEL was on. I'm thinking, "CRAP! (actually it started with an 'F' and was repeated numerous times loudly)...I just spent $300 from this paycheck on my Jeep and now something's broken. I call my buddy who I was just with...he's a mechanic...ask him if he's still at the shop and he says he just got home. Tell him my problem and he says, "Is it flashing?" "No." "You're fine...it'll get you home and we'll take a look at it tomorrow."
So I get it home...do the key on-off-on-off-on trick and get P0123.
Looked it up, TPS sensor code...great. At least it's cheap.
Run to the dealership on my way to work and ask our service manager about the code...he says most likely either TPS or something a bad PCM will do it. OR...here's something they recently dealt with...a loose throttle shaft will also cause issues...they learned this after replacing both the TPS AND the PCM didn't fix the problem. I went ahead and picked up a new TPS sensor ($45 at employee pricing...retails around $63 if I remember right). Installed it and around lunch time, light kicked off on its own. Sweetness...
By the end of the day though I noticed something interesting...my jerky 1-2 shifts and nearly stalling it on take-offs was no longer happening. At first I thought I was just driving exceptionally well...but now I'm not thinking it's so much of a coincidence. Apparently my TPS has been going bad...but just hasn't been bad enough to actually throw a code until last night.
Might help some of you folks out if you have the same issues...also, don't use non-OEM TPS sensors. Some folks say they're identical...but they are NOT. I put one from Autozone on my Jeep a while back thinking I had TPS issues...it worked for the most part but a few times a week, my Jeep would idle at 1200 RPMs for a few minutes. One I switched back to my stocker...problem vanished.