2000 rl surging idle speed
 

my rl was low on coolant ,now when it is park with the heat on the idle speed goes up and down every couple of seconds.when i turn off the heat the idle smooths out,though it is a little high.has anybody experienced this problem?

I had an idle problem before. Try cleaning the IAC valve on top of the throttle body. It commonly gets dirty and will stick sometimes.

did you bleed the air out? coolant flows through the idle valve and the temperature of the coolant is what controls the fast cold idle. If the coolant is not gettin gthere because of air in the system you will get a lopey idle.

I got the same problem and will but one of those funnels that burpes the radiator to hopefully cure mines. I already had the IAC and fast idle valve replaced.

replaced the fast idle and bled it thru the bleeder valve but still surges when its cold out?

It took a few visits to a foreign specialty shop to cure mines. When I asked him what finally did the trick instead of being specific like he normally is he said it took "tuning". I was just glad it was fixed so I didn't make a fuss. I can say it is a nuisance of a problem and I am sure it effects the economy with the engine revving up and down.
Good Luck