Need Help, Car's Demon Possessed!
 

I just bought a 94 Formula A4 with about 138K miles, and for starters, I had to replace the smog pump. But after doing that I noticed that the rpm's kept jumping up to over 1000 rpm at a stop. When I put it in park, it jumps up to over 2000. At stop lights, it likes to jerk forward even when I have my foot on the break.
It sounds like the engine is revving all by itself.

On the freeway when I floor the gas it jerks a lot over 70mph. It feels like it's shaking back and forth. Could it be from putting in 89 octane instead of 91? Before I had the new smog pump and with 91 octane it drove just fine.

Oh yeah, I think I need new headlight gears. Mine grind like crazy. The mechanic said I needed new headlight motors, but that's really expensive.
I was thinking getting the metal ones would fix the problem.

So I need some advice. Thanks.

Mine was doing the same thing..... Replaced the IAC and that fixed the reving problem, however the jerking on the highway got worse then turned it to a really bad miss, tore off the opticrap and it was so rusted inside I was surprised the car ran at all..