89 190e 2.6 starts great and idles when cold. However, once the engine reaches operating temperature and is shut down, it is very difficult to restart and keep idling long enough to put it into gear. If you can get it into gear, it will then drive fine until you come to a stop - where it will idle rough an/or stall. If you keep your foot on the gas and keep rpm's at 1,200 or so it will keep running fine. I am thinking that this is a OVP problem or maybe an oxygen sensor gone bad. Any thoughts?

Sounds like the OVP to me... you did a search, right?

The oxygen sensor would generate a "check engine" condition if the codes were pulled...the OVP would not.

I too, would point the fault to the OVP. Replacing it cured the same "hot start" problem I was having a few months ago.

Or,a leaking EHA.

The OVP and leaky EHA are more likely the problem than what I'll suggest; here it is anyway:

Fuel injectors leaking down into the cyls. Normally, this results in the car idling raggedly when restarting warm and the car has sat for a few mins., and not when you've stopped, got out and immediately restarted.

How can I determine if there is a leak in the EHA. I replaced the engine in my car about three years ago after the old one dropped a valve and destroyed the piston at about 200K. I purchased a salvage engine with only 30,000 miles on it and it showed up with with all of the components attached to it, including the intake manifold and EHA. When I swapped out the engines I could not get the car to run even though it would initially fire up. So, I swapped the EHA's and it came to life. Thereafter, I noticed a large gash in the rubber boot under the EHA that I had removed. Is this the type of leak you are talking about?

If you haven't done so already, try this site's SEARCH facility -> EHA. There are a number of posts that discuss leakage and location of the EHA.

Thanks Guys! The problem turned out to be the OVP relay. Replaced it yesterday and all starting/idle problems have gone away. Jayhawk