Based on all that you're now saying, you may or may not have multiple problems going on. If you want to try throwing expensive parts like a new TPS and O2 sensor at it hoping to solve things then fine. I'm sure they're getting a bit long in the tooth so it's not a total waste of money, but there is more testing and thinking you can do.

If the TPS isn't clicking and you're not getting continuity between pins 1 and 2 when the throttle plate is closed then there's a problem at the TPS, plain and simple. The engine doesn't know your foot is off the gas and that it needs to try maintaining minimum idle speed with the IAC valve. The TPS switch may well be internally worn/fouled, but there's always the chance it's just out of adjustment or the throttle plate isn't able to close all the way. That's why I suggested starting with the basics. Unlike some other engines, there's nothing overly complicated about these TPS switches, they simply detect whether the throttle is closed or wide open.

Your next step should be to loosen the TPS screws and rotate it fully counter-clockwise so there's no question about the switch being able to fully close and see if it will now click. Failing that, you could try removing it to check shaft movement and test across pins 1-2 with a meter. Although not at all standard practice, some people have had limited success trying to shoot contact cleaner in past the shaft or soak them in a solvent cleaner bath and repeatedly shaking, hoping to loosen and get some of the internal grunge away from the contacts, then throughly shaking dry. In general, replacement is recommended at that stage. If the throttle body throat and plate have a tendency to get dirty then the internals of the TPS switch are all the more likely to be dirty and needing replacement.

Now any problem at the TPS switch should be a separate issue from the fuel trim trouble code you have and a possible problem with the O2 sensor. About the only way they're related is if the fuel trim can't be maintained when the ECU doesn't know it's supposed to be maintaining idle and the engine is stumbling, rocking around and about to stall, which your comments now suggest is a distinct possibility, or when the engine is racing out of control. That's why I suggested once you've verified TPS operation, to clear the trouble codes and wait for them to come back. Also note that I only say a possible problem with the O2 sensor as there are a number of other possibilities that can affect fuel trim, such as vacuum leaks. The O2 sensor is just one of a number of inputs into the fuel trim program and is a separate engine management function from maintaining idle speed.

You need to first correct the problem at the TPS before worrying about the O2 sensor. Once you've got that dealt with, I recommend you check out the FAQ here. There are two good sections that deal with the O2 sensor: 700-900 Engine Sensors and 700-900 Oxygen Sensor Diagnosis

Once you've got the TPS sorted out, if the stumbling continues then Blindboy's thought about the CPS cable as an additional problem area is worth consideration. Inspect the cable carefully for damaged/split/worn sheathing, especially where it's near the metal tubing or other wear surfaces, at the clips, at the connector, and way down by the sensor on top of the bell housing (a common spot and usually fatal there). It's not always easy to see, though. Some days you only notice the damaged cable after you've got it removed for replacement. Wrapping damaged/worn areas in foil will only help restore the electrical shielding if it's touching bare braid or grounded to the chassis. The cables should be routed so it's kept away from wear surfaces, especially the metal tubing, but the two factory installed stand off clips on the pipes are often broken or missing at this age. I use nylon tubing and zip ties to fashion my own standoffs when needed, although cheap, small zip ties may not last all that long in the harsh environment back there -the large thicker black UV-proof industrial quality zip ties last longer.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now