This only happens when I am warming up my car or whenever I start it up. It idles between 1500-2000rpm and the needle jumps back and forth. After 5-8 mins, it idles gently to 1000rpm then slowly down to 500rpm. What is causing this?

 

Search Idle under Accord and you'll come up with alot on this subject.

 

yep, another one!!

 

hah. mine does the same too.

 

EGR valve?

 

THIS is very common... hmm.... why would that be?

 

question for you, when your idle jumps up and down do u observe your temp gauge, does it stay cool. if so your t-stat is bad. My car was doing that when i first bought it, idle would bounce up and down (thought it was possesed) and the temp gauge would never go up but it would not over heat. So anyway if it is that issue your T-stat is stuck open.

 

First thing I usually do when I have an idle surge problem is check to see if the radiator is full. Then I go and bleed out the cooling system. Air pockets in the cooling system can throw sensors off and cause idle problems..

 

how do you bleed the cooling system???

to the original poster...

you're problem might be the Idle Air Control Valve (IACV), if you search on this topic there is a post with pictures on how to repair

basically you get intake cleaner and clean the dam thing, its two big 12mm bolts to take off and some plugs, no big deal just a little messy with the intake cleaner

 

I replace the iacv, took the manifold apart to clean it, replaced theTPS, and Ithe RPMs are still jumping on idle between 1 to 2 RPMs. Frustrating!

 

Did you clean or replace the FITV?
What year and engine Accord?

 

I had to look that up but didn't find it for a 1999 Honda Accord V6 3.0. I did take it down to Honda and have them put it on a scan and the TPS and the IACV needed to be replaced. I had another scan done after cleaning and replacing parts. No codes come up and the check engine light is off.