Toyota guy had a problem like this, found out it was his IAT sensor--air intake sensor. After spending $1,000 at toyota.
---------------------------- Mr. P.V.'d formerly Droll Troll
*I'm posting this to all of the groups this has been active on, I'm sorry if
> any of you get doubles on this. *
>
> Happy Traveler et al,
>
> Well today I made some progress, not sure if its good progress, but hey,
> something is better than nothing. Before I go any further, lets make sure
> we're on the same page, this is the 1993 Ford F-150, 4.9L (300CID) Inline 6
> pickup with 185,000 miles that I am ready to drive into the bayou. Ok, we're
> up to speed.
>
> This morning the truck cranked and ran fine to work (note: once again, cool
> ambient temperature), it didn't seem to have a single problem. However,
> today the temperature managed to warm up and stay warm, and that played
> absolute hell on my truck. At lunch it pulled the same ol' stunt and just to
> recap, I cranked it, let it sit for a few seconds and upon applying the
> accelerator even a little bit the truck begins to choke, wheeze and stall
> uncontrollably, and that is once again, where I see black smoke and smell
> raw fuel. So, I did like any normal day and left it sitting and found
> another mode of transportation to lunch (once again, please don't ask) and
> came back later, about 4 hours later. This time, nothing changed, unlike
> other days. The temperature had cooled down some, but not much, but the
> truck still refused to run clean. So, being Mr. Inquisitive, I, for a lack
> of a better term, "dicked" with the coolant sensor, and low and behold, it
> came off in my hand! Yes, the upper gray connector portion separated from
> the lower portion on the truck, but didn't set a code; I had to physically
> remove the electrical connector for the Check Engine light to illuminate and
> then, unbelievably, it drove, "better". Now mind you, it wasn't great, it
> felt like it wanted to die, but it didn't.
>
> So, after some careful thought and pricing for different parts, I got in a
> working mood and the following was accomplished:
>
> New set of Motorcraft 44C plugs
>
> New Distributor Cap (after looking at the new one, I could see how
> corroded the original was!)
>
> New Rotor (also highly corroded)
>
> New Coolant Temperature Sensor
> I think there was a question here, on the 1993 there are two > sensors, one
> located on the engine block towards the rear of the engine which
> tells the gauge
> in the pickup the current engine temperature opperated by vacuum, I
> believe. The
> second one, this one, the one I changed, is on the front of the
> engine where the
> top radiator hose and heater hoses connect to the engine and it is
> my understanding
> that this sensor is the one that tells the computer what temperature
> everything is running
> at. Due to the fact that when I remove the plug on it and it puts
> out a check engine light,
> my guess is that this is correct, this is the one talking to the > ECM.
>
> New Air Filter
>
> Lets sidetrack for a moment and talk about these plugs; now, remember if you
> will, in my first post, I made a comment about a plug being stuck? Friends,
> this plug was STUCK, like chuck, or so they say. It took 30 minutes of work
> with an Air Impact Gun to get it to spin and then slowly working it out,
> turn by turn by turn. Amazingly, once it came free the plug was in decent
> shape, you could tell it was worn, but for all intents and purposes, it
> appeared to be in decent shape, the threads weren't galled up nor crossed
> and I really couldn't find an explanation as to why it was so tight, go
> figure. At least that's fixed and off my mind.
>
> So, back on track again, I guess tomorrow will really be the D-Day to see if
> any of the above fixed my problem or helped to pinpoint it. I spoke to a
> Motorcraft Serviceman today and the only other possible part that could be
> causing this would the fuel pressure regulator, and that is probably the
> next thing to get tested if this should again cause me problems. I'll keep
> everyone updated on wether she smokes and chokes or strokes.
>
> Justin
>
>