86 Delta 88 Stalling

I have an 86 delta 88 and i was driveing it on a cold day a few months back and i was one the freeway when i took my foot off the gas the engine died but started right back up again but after a few minutes i took my foot off the gas and it died again. I replaced the engine thermostat and took it for a driver around the block and i was comeing up to a turn and took my foot off the gas and it died again, So i took it back home and raised to idle speed above where it should be and the engine didn't stall once. I left the car sitting for a few weeks and on a warm day i put the idle below where it should be and took it out for a drive and it ran great and didn't even try to stall, So the next morning i put the idle back where it was supost to be it was cold and i took it to work and 10 minutes into the drive it died again. Does anyone know what could be causeing this because i am at a total loss and i would really like to keep this car running its been very good to me the last 4 year.

Jim, this is just a guess. I had a Dodge Spirit which would start fine, but in colder temperatures if you took your foot off the gas after it started it would stall. I spend a lot of time trying many different things until I found this valve on the throttle body which is motorized and is supposed to bleed air around the main throttle butterfly valve to control the idle speed (as best as I could figure it out) when you do not have your foot on the gas peddle. In looking at my Delta 88 manual it appears to have the same type of valve which they call an IAC or Idle Air Control valve. It has a square electrical connector with four electrical contacts. It is threaded into the throttle body and has a hex nut on it of about 1" or so.

It took a bit of nerve to replace this as on the Spirit the new valve was about $125 (Cdn). However, when I did, it worked perfectly after that. If you decide to replace it, be sure to look at a manual, are there is some setup you need to do, before putting the new one in.

Hope that helps,

Ron