Ford Repair: Ranger Stalls at low RPM, throttle position sensor, air control valve

Question
QUESTION: Hi James,I have an '89 2.3L cyl Ranger 4x4 5spd.  It has had a low rpm stall problem for ages, and no mechanics around here have been able to fix it.  I haul firewood on steep logging roads often in this truck and I lose power brakes and steering when she dies on me at low speeds or low rpms.  This is scary in mud or snow!
I replaced plugs & wires, replaced vacuum lines carefully, PCV lines and the valve and removed and cleaned both halves of the manifold and throttle body.  I was not able to clean throttle body to sparkling, but I did use a tooth brush.  I also replaced the EGR valve (ouch) and idle air control solenoid. I did the idle air valve first and noticed improvement but it didn't eliminate the issue.  Now it only stalls 20% of the time, usually at stop signs when shifting from 2nd.  What should I do next?  I have read your cleaning advice and I think I did that OK, should I use some foaming stuff inside the Throttle body? I only used carb and choke spray with tooth brush and rag. Lots of dirty road driving, could charcoal canister be clogged?  Fuel filter was also replaced recently.
Greatly appreciate any advice.
Brian

ANSWER: If you were able to clean the throttle body and it relieved most of the symptoms; then your issue is in the IAC(Idle Air Control Valve). Replace it and all should be fine.

---------- FOLLOW-UP ----------

QUESTION: Thanks for your speedy response.
But I did replace the IAC with a new part. (see orig. question)

I did fail to mention that I have a pretty rough and irratic idle sometimes.  Does that mean that my throttle body cleaning was not sucessful?  Or could there be some other problem?  People have suggested the throttle position sensor or the MAP sensor.  Should I test those? How?  I have not tried to get codes yet.  
Thanks again for your time.

Answer
I apologize for overlooking the fact that you had already replaced that part. If the throttle is irradic, you have a faulty TPS. Usually a good or even descent cleaning goes along way. Given that you have already done tha, you problem is elsewhere. However, your symptoms are not being caused by the MAP sensor. It will usually just cause you to burn rich/ dump fuel. Remove both the IAC and the TPS, then clean the throttle body. Replace the TPS with a new one and you should be good to go. Again, I apologize for the oversight. I am using my TV as a monitor for the time being and the picture is a little fuzzy until my LCD is replaced. Tnx for your patience.