Some time ago, I posted a thread about my 91 240 suddenly having a hard time idling. I posted the link below. I got a lot of good information from this board and was able to test a few things, but not all.

http://www.brickboard.com/RWD/volvo/1326578/220/240/260/280/91_240_wont_idle_cel_113_fast.html

Anyway, my mother apparently couldn't be bothered to fix the car, so she just drove it with the CEL and the hesitation until we had a bit of an intervention and made her get a new car because her safety and my sanity was at stake.

So, now I have the 240 back to tinker with on my spare time.

Here's the short of it - the CEL is on. The car actually idles okay once it adapts to whatever is causing the problem. If I reset the ECU, it will stall on idle until it relearns its adaptation and the CEL comes back on. CEL code is 113.

My initial suspicions were towards the AMM, but I recently tested it. 1.42V at engine off, 2.30V idle, 2.65V and climbing as I rev the throttle. I don't think the AMM is at fault on this one.

Here are all the other things I've checked:

Ground points, throttle body, hoses, IAC, pulled the intake, cleaned the fuel injectors, put on new seals, new IM gasket, checked spark plugs, and swore at its mother.

Im thinking O2 sensor at this point. If necessary, I will get down in the dirt and follow the wires, but if anyone would like to save me the trouble and let me know where the O2 sensor harness connects in the engine bay so I can test the sensor, I would be quite grateful. A photo would be wonderful.
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91 240 NA Auto 200k+ / 2001 BMW 330Ci 5spd / 1998 Toyota Camry 215k / 1999 Jeep Grand Cherokee 4.0L 2WD