You dont' have a power stage. Well, not exactly. The function of it was built into your ignition computer in the RF fender, on all distributor- triggered cars (LH1.0, 2.0, and 2.2, which you have). The power stage is a feature of LH 2.4 and 3.1 cars, 89-up.

The ignition computer is VERY robust, and though I've heard of people replacing them, I've yet to find a bad one. They just simply aren't the problem.

The coil could be a problem- replacing it would help isolate the issue. Used ones are easy to find in the junkyards.

There is a plug, which totally had me pulling my hair out, on a 87 240, causing intermittent stalling. It actually caused a previous owner to replace the coil at one point too. 2-pin grey plug, under/behind/next to the coil, in the wiring harness. I found mine plugged together, but not making good secure contact inside. Yours may be doing the same.

I also had stalling problems related to the plug at the air mass meter- check this, make sure it's fully seated, and the pins are clean and corrosion-free. Even more suspect because it was one of the things recently worked on in your car. Good luck with it!
--
Rob Bareiss, New London CT ::: 92 244-M47-207K ::: 90 745GL-M47-268K ::: 88 245DL-AW70-230K ::: 88 244 SOLD! 87 244 SOLD! Still looking for a bright red or black 244 with sunroof...