Cars engine rpm revs up periodically or shifts erratically

How did you check code's ? OBD2 scan tool ? There are more computers on your vehicle then just the PCM/ECM - engine computer . BCM - body control module , Air bag module , ABS - anti-lock brakes , instrument cluster etc.... Need a factory scan tool or someother professional type scan tool to read these codes. If the check engine (SES) light is on code's are stored in one of these other modules . Your best bet mite be to have a qualified repair shop check it out .(not dealer )

Engine light on? Sounds like the input speed sensor.

VUE will not move - SaturnFans.com Forums

www.saturnfans.com > ... > Models > Saturn Vue > Vue Tech

Jan 8, 2010 - 11 posts - ‎9 authors
The owner says it will not move and it is the transmission that needs to be replaced. Itwill start and run but when in gear it will not move. Is this a ... 99 SL1 Manual won't go into gear
6 posts
May 12, 2009
Car won't shift into drive...
8 posts
Nov 12, 2007
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Saturn Vue Transmission Problems - Car Forums at Edmunds.com

forums.edmunds.com > Saturn > Saturn VUE

Jan 26, 2013 - 30 posts - ‎17 authors
Learn more about Saturn VUE at the Edmunds.com Car Forums! ... miles and transmission is stuck i can feel it go into reverse and move ,but not for .... within a few weeks it started popping out of 3rd gear and makes a grinding noice, .... this bolt until I already had done so, now, it will not shift from 2nd to 3rd. More results from forums.edmunds.com

possible that there is an issue with the torque converter clutch servo/solenoid operation
take it to an accredited service center and have it properly diagnosed

I would have the transmission checked, it sounds like it is not shifting. The transmission is controlled by computer and it can sense problems and return fault codes for what it finds on the test and in its memory.

Had the same problem. In my case, the wiring harness was scraping against the vibrating motor and wore through the insulation. This caused the computer to think the throttle position sensor was bad and the RPMs were erratic. The engine light came on and indicated TPS. A short time later, more of the wires became damaged and the engine started missing cylinders. My problem was at the top rear of the engine where the harness runs over a metal stud (right behind the valve cover). Check your wiring harness. Not an easy find until you actually look for it specifically.

the coolant temp sensor is located at rear of engine oppisit the timing belt under rear of intake manifold.

Here is the definition of the code in GM manual:
P0128 - Coolant Thermostat Below Thermostat Regulating Temperature, this indicates the engine is running cold, u need a thermostat

Hate to be the bearer of bad news but mine failed at 29K and became undriveable at 31K and after years of hard handling, I treated that car like it was Christmas tree ornaments, fully expecting it to last until I am dead; the engine failed at 57,600. It's gone and I'm still breathing. It was the last GM anything I will ever own.