when i start my car the idle jumps up and down form 1500 to 1000rpm, after i drive it goes away for a while but when its in neutral it comes back. Any clue what this is thanks.

 

small leak in the intake can cause odd idling... whats your setup? Also, on warm up the engine will set its own idle until it warms up, but that doesnt sound right with it jumping up and down...

sohc

 

How can an idle jump up from 1500rpm to 1000rpm. Can you please explain a little better?

 

Oh, I get it. Look for a vaccum leak.

 

well im a turbo accord and i just did the auto to manual swap, but tis started the day before the auto to manual swap. so u mean inspect every vaccum hose. i think ill just replace them all. any other possibilities

 

Fast Idle Valve.. that's the valve that warms up your car when its cold.. or at least it makes your engine idle higher when its cold so that it can warm up... alot of us here had similar problems do a search on it cuz there have been a few threads on it i believe