Help Please! Rpm/shifting Issue

[Wojtek5884]

Hello everyone!



First time poster, long time lurker and I was hoping I could maybe get some help from you all as I'm running out of ideas.



I'm having some RPM/shifting issues with 08 ISF. Here are the symptoms so far:

• Unnaturally high RPMs in Neutral/Park whether on a cold start or after being warmed up. Drop back down in Reverse/Drive.
• Standing
  up hill, if I put the car in neutral and let off the brake, it wont
  roll back until I tap the gas. It will then rollback for a second and
  then stop once again.
• RPMs have to go much higher than before to shift into 2nd, 3rd, etc gear and the car jerks during the lower gears.
• When
  in bumper to bumper traffic the jerking is much more noticeable as the
  car keeps shifting between low gears. (I drive in chicago traffic into
  the city for work so it gets old quick haha)
• Under wide open
  throttle and then release the RPMs will drop very quickly but then once
  they hit 2-3k they will hang and bounce up before going back down. Never
  did this early on when I bought the car.
• When releasing
  throttle, the car decelerates very slowly and wont come to a complete
  stop until the brake is fully pressed down and brake has
  pressure/pushback even when at a stop and car will lunge forward
  slightly when brake is released.

Here's what I've checked/had done.

• Replaced throttle body, problem continued, put old one back.
• Checked for vacuum leaks, apparently none.
• Had transmission reflashed at dealer, same problem.
• Had ECU reset, same problem.
• Had data logged/read for an hour, nothing out of ordinary apparently.
• Only thing that's obvious is that one of my cats is a bit clogged but mechanic friend said it shouldn't be causing it.
• Also said MAF should not be issue either.

No
idea what it could be and it's been driving (haha a pun) me nuts. It's
my daily driver too so this worries me every day. To top it off, no
check engine light so I'm completely in the dark!



Thanks in advance everyone! Hope I can figure out an answer soon.