For starters, My apologies, Jwho, it never occured to me that I was
*bragging* by saying that I got 2 responses from the ford group.
Never looked much there before, but now that I have, I guess I WAS
bragging!


OK, here's the story...

Last night the suspense was killing me, so I went out and worked on
my truck between passing bands of rain. The OBD codes indicated that I
had trouble with either the throttle position sensor, or the EGR valve
position sensor, or both. Changing or testing the TP sensor requires
removing the throttle body, so I took it off. Pretty easy maybe a 20
minute job. I also took off the EGR position sensor, snapping off one
of the 8-32 screws that hold it on. Blah. Soft, cheesey screw, drilled
out and cleaned up the threads pretty easily (metalworking content, no
longer OT. Heh). Brought both into shop where it was not raining and I
had light.

The idle air valve came off with the throttle body, so I took it off.
It looked pretty clean inside, resistance tested OK, and the plunger
opened when I jazzed it with 12V. I deemed it vindicated.

The EGR sensor test outlined in the manual called for some voltage
tests in the vehicle, key on, engine off. It was raining out again,
and I was sick of getting wet. I did an ohmmeter test. It appears to
be a simple 3 wire pot, whose wiper is actuated by a plunger thing
that rests on the EGR valve diaphram. It "looked like" it was working
OK, but that was not the offical test, and I did not know what the
correct resistance should be.

I tested the TP sensor according to the info from the Autozone site,
a basic resistance test of what also appears to be a pot. It tested OK
too.

But I was still suspicous. I fix electrical/electronic stuff for a
living, and have seen lots of pots measure OK but still fail in use
due to "dead spots" in their range of motion. Particularly with these
sort of position feedback pots that tend to spend much of their lives
moving through only a small percentage of their range. Those can be
difficult to find with an ohmmeter. So I called the local autozone
place, they checked and said the had both parts, so I ran down there.
As it turned out, they didn't *really* have the TP sensor, just the
EGR one. So I plunked down my 28 bucks, and headed to the next parts
place. Got the TP sensor there ($45) came home and when there was a
break in the rain, ran out and installed all of my cool new stuff.

The bottom line is that the truck started up, ran fine and even
idled! In gear, out of gear, a/c running, it still idled. Way cool. I
drove it to work and just around a bit today, and it looks like I got
it.

So I still do not know which of the 2 parts was the culprit. Could
still have been both. I am not really inclined to put one of the old
ones back just for the sake of an experiment. At this point, I am just
glad it runs. But as the TP sensor is harder to change, and it is
ALWAYS the more difficult to get at part that is bad, Larry gets to
say "I told ya so..."

Go ahead, I can take it.

And, Larry, as to weather Gunner qualifies as "famous" or "infamous"
is a bit of semantics that I REFUSE to get in the middle of!!

Thanks again to all who responded. I appreciate your all taking the
time. like I said, you guys are awesome.

Watch your mailbox for the check for $37.50. That's right, you just
keep watching...


Al A.