My car hasn't been idling very well, and after pulling the transmission to replace all the seals, its running even worse. The idle is rough, it will rev up and down and stall out when first started, and then vibrates the car at stop signs. Also, when I first start driving, the car is very sluggish and doesn't respond to pressing on the gas, I can't manage to go more than 10mph on the slight hill by my house. If I pull over and restart the car, however, it does ok, though occasionally, it will hestitate, as though my foot slipped off the gas or something. The only code that I am getting is 113 (fuel trim too lean or too rich).
The FPR and spark plugs are new, the AMM was replaced with one off another car. I previously had trouble with an erratic idle (going from really high to stalling out), though it seemed to get better when I swapped the ECU for the newer model.
By the way, the transmission work was done by my mechanic boyfriend who knows nothing about volvos. Is there anything he could have screwed up, or is it just coincidence that the car got worse now?
Any suggestions on what I should look for would be greatly appreciated. Thanks (and sorry for the long post)!

What about the RPM sensor on the transmission bell housing?

What is the shelf life of this sensor?

Should it be replaced after a certain mileage just for good measure?

Thanks.
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'89 244DL M47 165K miles

....that I should check for vacuum leaks, clean the throttle body, check the coolant temp sensor, IAC, and AMM. Is all this correct? Anything else?

You can do your flame trap too.
You may want to check the brake booster check valve (little white thingy in the booster).

How is the hose that goes from the AMM to the throttle body? Check for small cracks.

Throttle body should be done first, this may solve all your iddle problems.

Good luck Laine.
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'89 244DL M47 165K miles

I'd check the IAC first, recommended test is tapping it with a stick when the idle is rough.

Tapping the IAC with a stick will sometimes free the valve up, you can also try to clean it with carb/injector cleaner - sometimes that works. More than often you will need to replace it as it is so old it is worn out of spec or frozen up. Vacuum leaks and the IAC are good first places to start looking regarding the problem you describe.