Emergency help. PO122

I have a 2001 Checy Cavalier 2.2L with 48,600 miles on it. Nothing but problems. Last Friday at 31 MPH the car died on me so I put it in neutral and started it up again but the traction light stayed on. I pulled to the side of the road and shut the car off. I started it up again and the light was off but when I put it in gear the Trans slammed into gear really hard. So I shut it off and it did it again after restarting the car. When I started to drive away the trans would not change gears. After about 30 seconds of driving the trans jumped and it went back to normal. I took it to a trans shop and the ran the code and it came back as PO122 a TPS sensor. A few months ago my dash started acting up as well where some lights wouldnt work and you cannot read the odemeter. I also have a code of PO440 EVAP system failure for a few months as well. I keep turning that light off but I guess my question is,the trans shop said it is an electrical problem that could also be possibly causing the dash problem but would a TPS problem causer all of these problems or what. I just have absolutly no clue where to go from here. Please help me if anyone has any ideas. The trans shop also said that all the sensors are wired to where if the TPS isnt workign right it will not allow the trans to shift gears. Does this make sense or is there something in the electrical that I am missing? The dash is whats really getting me now. Thank you and please let me know if anyone has any ideas. Thank you again. My email is [email protected]

I also have a code of PO440 EVAP system failure for a few months as well.

The EVAP system failure can be one of several things. It may be the gasket on your gas cap is bad and causing a leak, or just your gas cap is loose. There may also be a vaccuum hose leak.

Here is some more info on that:
Diagnostic trouble code (DTC) #P0440 concerns the EVAP system. Evaporative leak detection strategy is based on applying vacuum to EVAP system and monitoring vacuum decay. The Powertrain Control Module (PCM) monitors vacuum level by means of a fuel tank vacuum sensor input. At a predetermined time, EVAP purge solenoid and EVAP vent solenoid are turned on. This allows engine vacuum to draw a small vacuum on the entire EVAP system. Whenever a sufficient vacuum level cannot be achieved, a large leak or faulty EVAP purge solenoid is indicated, consequently the check engine lamp is illuminated. Before you get to aggressive on repairs a simply suggestion would be to make sure the fuel cap is tighten correctly and/or replace fuel cap and have the DTC cleared. Fuel cap problems can regularly set the specific DTC in question.
http://class.heraldnet.com/underthehood/index.cfm?id=845

I already tried replacing the gas cap but the check engine light still comes on...Now witht he weather changing cooler the light is coming on more frequently...Plus with my dash lights half out,my odemeter doesnt light up and its all blurred and also when I reset the code one time before the rest of the warning lights came on,lost all my guages and dash lights so I unplugged the battery and it went back to the way it was before...As for the EVAP system I just cannot figure it out...I took it to a shop one tiem and they couldnt figure it out either...UI am confused...

I have a 04 Cavalier, the ecotec is nice, at least better than any of the other Cavaliers in the past. I do know where you can get a turbo and anything else that you need on your ecotec.