I have a 97 prelude base model. When the car is cold the revs jump and fall about five hundred rpms. When the car is at operating temp it idles fine. I was told it could be my cold start injectors. How can I test for this. I tried to see if it would throw a code but came up with nothing. Any ideas?

 

is there a check engine light... if so could be iac or tps other than that i dunno man

 

pull the tps when its jumping up and down, and see if it stops. If it does then its your tps, if not that its either a vaccum leak, or iac

 

My prelude did the same thing and it was the eacv..

 

Does the 97 Prelude even have a Cold Start Injector?

 

EVAC purge, check the hoses...

you might get away with replacing them with much STIFFER hoses