Chrysler Repair: high idle on 85 2.2L non-turbo; power loss light, light greetings, coolant temp

Question
Greetings Roland,
For some time my 85 Dodge 600 convert. w/ 2.2L non-turbo & auto trans. was acting strangely- sometimes idling too high w/ no "idiot light" indicators on the dash, and other times appearing to have too rich a fuel mixture (noticeable hesitation on accelerating & wet, black exhaust along with the "power loss" light on. These conditions were intermittent- I'd go for months, starting the car every day without either problem, then, out of the blue, it would reappear. It was often "cured" by turning the key off and on again very quickly (presumably resetting something-?) or by disconnecting and reconnecting a "pigtail" type connector which ran wires to (among other things) the TPS and injector. More recently, these "cures" didn't work. About a week ago, I followed your "ON-OFF-ON-OFF-ON & count flashes" procedure and got a series of codes, though not always consistent.  The one constant was a "24" so I just replaced the TPS. Also sprayed PB blaster on all the linkage, and carb cleaner down the throat of the throttle body?/fuel injector?  Immediately following, codes were clear (just the 55 flashed) but the high idle problem remains, also now the "power loss" is lit as well.  Any ideas of how to fix?  Thanks for your help.

Answer
Hi Greg,
If you are sure that there are no codes, other than 55, and yet the power loss light is on, that means either the throttle position, the coolant temp sensor, or the MAP sensor signal is missing in action or far off-value. I would be inclined to look at the wiring connections between those sensors and the logic module in the cabin by the right kick panel. So if you have the wiring diagram I would verify that they are patent and that the signal is not grounded or shorted to an adjacent wire in the harness. The TPS wire is right over the manifold so it can get melted, and you might have an open vacuum line to the MAP which is located in the cabin, on the logic module.
The other possibility is that the fuel injector is worn out. When the engine is idling take a look at the spray pattern that hits the throttle plate: it should be a very fine spray with no drops. Similarly, when a helper shuts off the engine there should be no after drip. The injector can begin to drip which would of course result in a too rich mixture.
Let me know if you need specific on those sensors' wires.
Roland