OK, we're talking about the 1987 190E 2.6 w/135k miles. For a couple months it was stalling, but would restart after 3-4 seconds of turning. Yesterday it stalled and wouldn't restart. After an hour it would. Since I needed to have my car operational ASAP, I had to go to the dealer for the OVP and $100 later it was mine. Install took a quick 2 minutes, and it started right up. After a quick 1 mile ride, it stalled again, but is re-startable (after 3-5 seconds of cranking) .
The old OVP had a part number of 201 540 32 45 and had only seven pins; the new one has a part number of 201 540 37 45 and has nine pins (the plug does accept 9 pins). I assume the new OVP is compatible. It is the same size and has the correct bracket.
So, what should I do next? I don't feel like dumping $100 here, $100 there. FYI, I had the ignition coil replaced 3 years ago and the o2 sensor replaced about 4 - 4 1/2 years ago. I imagine it is a relay problem of some sort. What do you guys think?