halleva

HELP!!!! Since February I have been trying to get my 1992 F150 302 V8 to run properly! I am at my wits end. It wants to stall as soon as it starts. The idle speed has a mind of it's own. It speeds up it slows down etc. When I finally feel the courage to drive away I can expect a stall, hesitation etc. And when I manage to get it to 50 miles per hour I often get a "bucking" sensation. The truck is pretty much un useable since February. So, this is what I have tried so far: New wires, new plugs, new distributor cap, new rotor, new IAC valve, new TPS sensor and new MAP sensor. The engine light is on almost all of the time and the codes are: 22/53/33/81. I have checked the EGR valve with and without a vacuum pump. The stem and diaphragm move when vacuum is applied and the engine will run rough and want to stall if I apply vacuum to the valve in idle which I believe signals the valve working fine. I have sprayed carb cleaner on the closed diaphragm with the engine in idle and there is no change in idle speed which I believe it signals the diaphragm is not leaking. I have puled the vacuum line to the valve and there is always a very weak vacuum but then again I don't know how much vacuum there should be. I have revved the engine and watched the valve stem and it will not open with just the truck's vacuum hose attached to the port. I don't know what to do next without spending more and more money changing parts and not knowing what I can expect. If anyone has any other suggestions I would be much obliged.

fordmech604

33 rc EGR valve opening not detected
22 orc Manifold Absolute Pressure (MAP) sensor out of Self-Test range
53 oc TP above maximum voltage
81 o Air Management 2 (AM2) circuit failure

The first thing I would check is TP Voltage, At idle check the green wire at the TP sensor to ground, should be .99 volts.
Also check for a vacuum leak between the upper and lower intake manifolds.
I would not worry about the code 81 at this time.
Also make sure you have good vacuum at the MAP sensor.
You might also want to pull the vacuum line off the fuel pressure regulator, and make sure there in no fuel coming out from that port on the regulator.

halleva

Thank you very much for the suggestions. I will try what you said but first I need to learn what the acronym TP stands for and then locate where this sensor is located. I also seem to need a piece of equipment to test the voltage. I believe there is good vacuum at the MAP sensor. I check that often. And the thing is, when I pull the vacuum hose off of the MAP, the engine idle speeds up, which helps the engine run a little higher. One last question please, how do I check for a vacuum leak between the upper and lower intake manifolds? I ask because I believe a friend of mine used a propane torch to check for vacuum leaks in that area for me and did not find any. Thanks so much for your time.