Real fast idle

[Glen]

When I first start the car cold, the rpm will jump to 2000 rpm, after a few sec. it will drop to 1000 rpm then go back to 2000. It will do this 3 or 4 times then idle at 650. If I put it in gear as soon as I start it, it will idle fine. After that when I drive it the rpm will go to 1500 - 2000 and stay there. that is about 65 mph. Fine on the freeway, hell in town. When I slow down the rpm will drop after 15 to 20 sec. As soon as I touch the gas it will go back up. When I am going down the road and hit the gas quickly to the floor and let it go, the Check Engine light will come on for a few sec the go off.
I ran the codes and got a 34 and 53.
I don't know where to start on this one. The only thing I have done in the past few months is replace the gas tank.

[Glen]

Just to let ya all know, I pulled of the cruise control cable and it seams to have fixed it.

[jpc]

I was having a similar issue, very high idle even after a few minutes of driving.

Greasing the fast idle cam didn't fix it.

Removing cruise control didn't fix it.

I managed to get a peek at the engine as the issue was happening, and the fast idle cam had engaged. So I have a new fast idle cam thermostat on order, maybe that will fix it. Until then, I backed the fast idle adjustment screw way off, so the car is safe to drive.

[Glen]

You have CFI, I have EFI. I don't have a fast idle cam.Thanks for the reply.

[miamibob]

IAC???? Have you cleaned out the Throttle Body and plate?

[Glen]

Not yet, that's next on the list. Along with everything else that I can clean. The car only has 255,000 miles on it, so I guess I will have to replace a few things.