Chrysler Repair: 2000 chysler cirrus: code 0171, throttle position sensor, coolant temp

Question
my 2.5 liter cirrus is wacked out, just driving normally, all the sudden, running on just couple cylinders,  plugged in with scanner, getting a 0171-bank 1 too lean?  then of course the multiple misfre codes, but i think that is result of other problem?  i let it sit for couple hours and wouldnt you know it.  it started and ran somewhat descent for few days, thensriving home tonight, seems like gas gage was at the same spot, about just under 1/2 full and same thing, had to stop, couldnt get any power out of it, tryed dry gas and tryed diluting gas with 5 gallons of fresh stuff, no help, even through few plugs in it, no help almost acts like it will start and run o.k. after it sits?  please help roland

Answer
Hi Greg,
On your question, Greg, only if the problem began pretty quickly after the start up and the code was for too rich, then I would suspect the coolant temp sensor was off-value and not leaning out the mixture properly as the engine warmed. But you code says too lean. So that would shift the attention to the O2 sensor as that, if defecive, would produce a one-sided code were that side's sensor to be bad. That might be where to start:  see what its voltage is, reading between the upstream sensor's black/dark green and black wires. It should be about 0.5V with the engine running and warmed up. Compare to the other side's sensor (tan/white vs black wires). If they differ significantly, or it reads 1.0 or 0.1V then I would replace that sensor.
Roland


It is good you got a code, and I would continue to check for codes which may also be revealed during the abnormal function.
The causes are possibly the following:
restricted fuel supply line
fuel pump inlet strainer plugged
fuel pump module problem
oxygen sensor defective
   "         signal shorted to ground
   "        heater operation
Throttle position sensor voltage greater than 0.92V when closed
TPS sensor sweep intermittent
MAP sensor operation
engine coolant temp sensor function off value
engine mechanical problem
powertrain control module problem

I would suggest looking at these in order, skipping over the ones that require alot of removal effort to check, just for efficiency.
There are about 4 pages in the manual I could xerox and send you which you could consider as a step-by-step approach but without detail on each of the items. Do you have a shop manual of any sort about the 2.5L V-6?
Let me know using the 'thank and rate' tab, listing a postal mailing address if you want the pages.
Roland