Resolution. Guess what. It WAS the MAF sensor. I picked up a cheap $40 one and swapped them out. All the weirdness stopped. How this had anything to do with the cooling system is beyond me.

Update. Talked to a relative expert about issue and he agreed that it did not sound like it was actually the MAF sensor causing the problem. He suggested i clean the throttle body, so I did. It was surprisingly clean. With minimal crap accumulated on the throat or the butterfly; certainly not enough...

I know this has been touched on in a few other threads; I've read them all and this is a little different. About 5 weeks ago I pulled in the garage, shut the engine off and the cooling fan continued to run for about 20 minutes. It had been a very hot day, but the temp gauge never rose above normal o...

OK, the replacement rear O2 sensor was installed 2 days ago. At this point I have driven the cycle, and the check engine light has not come on. SOMETHING TO REMEMBER: Apparently a bad rear sensor can make the OBD think the front one is bad. For those of you who are taking notes; The code I kept gett...

Well, the code was 1033 I think (stage 1 slow to respond..."); It was the same code I have gotten on 3 different sensors over the course of 1 week. And each time, the check engine light came on as soon as I had completed the initialization cycle. I talked to one of the techs at a local dealersh...

-A day later. I had been driving for a couple months with, presumably, a bad O2 sensor (the front one -according to the code generated, was responding slowly). So I replaced it with an OEM Bosch, and took it by a local Volvo specialist to check the readings and reset. When we hooked it up to the rat...