97 Saturn wagon possesed

The throttle moves by itself, and the arrow of the temp indicator goes up and down randomly.
Sometimes it won’t start, or starts and then dies.
The check engine light is not on, so my mechanic says he doesn’t know what to fix and it might be the computer and I have to take it to the dealer.
Well, there is no Saturn dealer, so I’m taking it to a Chevy dealer that is doing Saturn repairs.
I have no idea who these guys are, or if they can be trusted.
Any ideas what I might expect?
I just had a new air intact put in and a throttle sensor about a year ago.
The antifreeze was recently flushed.
Thanks.

Does the throttle (gas pedal) actually physically move by itself or does the engine speed (RPM) change?
I’m betting the rpms change, and the temp gauge fluctuates when this happens as well.
Typical symptoms of a bad engine coolant temperature sensor and/or wiring harness. Common problem on these cars.

the throttle is moving.
wouldn’t the check engine light go on if it had a bad sensor?

This is not a drive by wire throttle, so something has to be moving the throttle. Does the throttle stick while at idle, that is does it take more force to move the throttle from idle than it does to move while driving?

The EGR is right behind the throttle plate so it tends to gum it up, especially when the EGR valve starts sticking open, which it is prone to do. When the EGR sticks open far enough, it will set a code, but there is a period where it will stick open just enough to gum things up, but not open far enough to set the code.

Another issue these have is a vacuum leak around the intake manifold gasket at the #1 cylinder. This port is not well supported and only uses three bolts. When it starts leaking, the idle will go up and down, but the throttle pedal will not move.

What did you mean by “air intact”?