[highrisk]

Originally Posted by SRGN

You are on the right track. Vacuum leaks can be an issue when they aren't obvious, everything from a stuck PCV to a failing brake booster can throw it off. Have even seen leaks from incorrect valve cover bolts protruding into the intake ports and causing a leak. What are your MAP readings at idle and cruise? Hook up a vacuum gauge and see if the numbers match. There's a lot of charts to correlate inches of vacuum to kPa. You can also try setting it to open loop so there's no correction if you have a failing O2 sensor, it runs off the base fuel map when you do that. It's difficult to diagnose over the internet, so knowing what isn't an issue is going to help narrow things down.

Sorry for the delay, for some reason I am not getting notified that someone has posted on a thread I am subscribed to. It ended up being the IAC Valve. Once I replaced it and drove the car to go through a new learning process it settled down and is driving normal again. Didn't think it could be a vacuum leak, everything is new. The car only has 1900 miles since the restoration was completed. But then again, anything can happen.

Thanks for the help,
Dale