Engine surges at idle 1992 honda prelude 2ltr auto also when stationary and in gear will lurch forward

Air/idle control sensor

sometimes this is due to a bad harness wire, if there is any way you can get another wire to test it, that will be a first step.

have your water pump checked

honda prelude 1990 4 spd manual trans ac ls model. accelorates normally and in between all gear changes engine does not slow down to 1000 rpm it remains at 2000 rpm.

sounds like the throttle body

There is a warm up valve on the throttle body(should have 2 small coolant hoses). remove the valve and have someone start the car while you block the port to the valve on the intake. If that clears up the problem you can cut a piece of cardboard to mount in between the valve and intake.should straighten it out.

is everything stock? and you have catalitic converter in place?

Stop by Schucks auto supply and have them run the codes. i'm sure there is a code if you cant pass emissions. your check engine light bulb is probably out.

and usually the first cause is the first o2 sensor.

You can download the entire manual from www.pdftown.com
Here is the link to the shop manual for the 88 prelude that I used to do my Cam Belt.
http://pdftown.com/Honda-Prelude-1988-Service-Manual.html
Hope this helps...

Consider replacing the rotary idle air control valve, and clean your throttle body.

Check your idle control valve. You might have to replace it, 80-90 bucks new. Or see if there is an air leak from the intake manifold. had the same problem.