Honda Prelude Forum - PreludeDriver.com

ok so i have an 87 prelude si with the 2.0 fi engine. my car starts fine and everything but when i stop at a light my idle drops to around 400-500 and if i sit at the light for a minute it goes back up to 900, but it takes a while. i was wondering how i could fix this. could this be a problem with one of the sensors?
please help its kind of embarrassing when people get in my car and they ask if its going to die at a stop light.

Is your ECU light flashing at all?

Do you sometimes have trouble starting the car when the engine is hot?

It definitely sound like a sensor problem. It could also be that your idle is set too low and the sensors are working overtime trying to compensate for it.

Have a look in the manual (see manuals section above) about setting the idle correctly. Also, check to make sure your ECU isn't throwing any error codes.

Welcome to the forums!

cool thanks. ill check those tomorrow when i get home from school. i will let you know if i find anything.and yes when the car is hot it is more difficult to start than in the morning when it is cold.

Let us know what you find.

ok so i checked my ecu and it is not throwing off any codes. would you happen to know how to adjust the idle?

I've attached a file from the relevant page of the 1985 Prelude Shop Manual Supplement. It applies to your car.