when i'm driving (97 max gle) at 20-40 mph and i let go of the gas to let the car coast, my rpm's drop down to 500 and then dip back up...happens everytime i let go of the gas..do you know what the problem could be?

-Thanks

 

Does the car idle normal (600-900) when not moving?

 

its at about 500 when its in drive, but goes back to around 700 in park or neutralfor some reason this only happens in really cold weather...when its warmer out there it idles normally and my rpms dont drop when i'm coasting...but anything below 35 degrees it will definitely happen...any thoughts?

 

weak battery?

 

uhhhh no.. ok i have the same problem.. and cat figure it out either... i think it might be the IACV or a vacum leak

 

well fwiw i replaced my battery today and my idle is back to normal...

But it's most likely the TB, IACV, egr. Search the threads there's a lot of info on these parts, including links on cleaning

 

thats doesnt have much to do with anyting unless ur alternator is going bad... thanks for editing ur post...