Fuel mileage very poor?

Temp sender near tstat is 42.9K @ 59 degrees F

Air charge sensor was the same, I removed it to make sure it wasn't full of carbon, it was okay. I could see it drop in resistance when I had it in the sunlight as it was in a cold intake when I first measured it. TPS has been replaced. Something else I noticed is when I'm driving 30-35 MPH and step on the gas it just sits there. Doesn't accelerate unless you stick it to the floor and the tranny downshifts. It doesn't do it all the time. WIth as much gas that it's sucking I would expect it to fly, but for a 302 it's a real dog. I checked the TPS and it seems to change resistance evenly from closed to wide open throttle. I also had the EGR off to check, I had to replace it a while back because it was clogged up with carbon. It was okay

TPS goes.98V to 4.5V closed to open throttle. I think it needs an exorcist; When checking the O2 sensor, I know I had a good ground and good contact on the connector. The voltage jumped all over from.08V to.9V when it was idling. This is the 4th O2 sensor in this POS. It was fully warmed up. The TPS voltage is exactly what it says in the Haynes manual. O2 voltage is not even close. There's 12V on the O2 sensor heater as it should be. I tried probing on the gray/blue wire many times and got the same result. I know the meter isn't flaky because I tried another with the same results. There was no difference in voltage when opening a vacuum line or spraying TB cleaner. The gray/red wire is common to most of the sensors, including the O2. I will check continuity from the O2 sensor connector back to the PCM tonight after work. Is the gray/red wire supposed to be chassis ground, or is it unique to the PCM? Should I measure the voltage across the O2 sensor (gray/blue HI to gray/red LO)? Or is that possibly why the voltage was so erratic because of using chassis ground as a reference?

"Something else I noticed is when I'm driving 30-35 MPH and step on the gas it just sits there. Doesn't accelerate unless you stick it to the floor and the tranny downshifts."

I had a mileage issue just recently and when I towed a boat tranny went out. Replaced seal, filter, and black fluid and no longer have proper shifting. I suspect the torque converter went out on mine. I'll keep adding to my question for interested parties.

Look to see if your rpms fluctuate while driving I believe that may contribute to slippage, whether TC, gears, or bands I have no clue and I am planning on doing my first rebuild, so you can understand my experience level, i.E. Novice.

Thanks for the input, drobb0151. The engine RPM doesn't change at all untill you put it all the way to the floor and it downshifts. The fact that the exhaust is black indicates there's something definitely wrong with combustion. At this point I'll look at anything that might be wrong. Fords are unreliable, nothing but trouble, and I don't think I will ever buy another. And they get PO'ed when Hyundai, Toyota and Honda takes their customers away.

I ended up backprobing pin 29 of the PCM (O2 sensor input). The engine was at normal operating temp. I started it up and it read about.35 to.40 V. I sprayed some carb cleaner in the TB and it jumped to a little over.90V and then returned back to.35-.40V or so. After a couple minutes it started jumping all over the place and I could hear the eng. RPMs change erratically. It was a high and very unstable reading, which indicates a very rich condition. It seems the O2 sensor works but something is causing the injectors to be "on" too long regardless of the O2 sensor input.

I have a new MAP sensor and it checks okay according to my Haynes manual. I pulled the SPOUT connector and base timing was 10 deg. B TDC (5 ticks to the RIGHT of 0 deg.). I reconnected the SPOUT and started the engine and at idle it was 2 deg AFTER TDC (1 tick to LEFT of 0 deg. Mark)and would go as far as 10 deg. AFTER TDC as speed increases. Whoah! Whats causing the timimg to retard so badly? The higher the RPM the more advance (a few more degrees BEFORE TDC) so you have spark before the piston is at the top of travel, right? If I'm seeing this right, I'm getting spark when the piston is on a downward stroke. Timing marks are on the harmonic balancer and indicate B or A 0 deg. I checked things twice, same result. Is there anything that could cause the PCM to retard the timing that much, or has the PCM lost its mind?

I did some more checking, I checked the PS pressure switch, it read open. I started the truck and turned the wheel all the way right and the switch closed (which is what I would expect it to do.) I straightened the wheel and immediately connected the harness and I could hear a definite change in the RPMs, connecting and disconnecting would change RPMs. I suspect the PS switch sticks closed. Would this 1 input cause such a drastic timing change (see last message)? I will be getting a new switch, I will install and let you know what happens. Anthing else I should check in the meantime?

I put in the new PS pressure switch and timing is normal now! I let it run a few minutes, turned the steering hard left and back, timing was >12 deg. Before TDC and would increase advance as RFPM increased. I don't have a tach, but it seems the idle is kinda high and fluctuates. It will idle fast when you start it up, even when it is warmed up. I have a fairly new idle speed control motor on it. Any ideas what to check?

1993 Ford F150 V8 Four Wheel Drive Automatic

When I bought this truck It got about 15-16 mpg now it gets 8-9 mpg whats wrong?

No difference at all. I took it to the Ford dealer and they checked the PCM and ALL the sensors. They found nothing wrong. I drove it with the new PS switch connected, no change. I drove it with PS switch disconnected, no change. Still got <10 MPG. Checked the timing after driving it today and the stupid thing is 2 deg AFTER TDC at idle(SPOUT connected). Ford said the PCM is fine. They checked the timing and it was okay THEN also. The only thing they found was the TPS was at.9V at idle and it should be about.67V. I seriously doubt the TPS is going to make that PCM retard the timing like that. I think my erratic idle is nothing more than the PCM going open loop all the time. What could be making this thing go open loop all the time?

I bought a new TPS and installed it and have it set so it reads.709V at closed throttle and will go to 4.7V at wide open. (Gray/white wire).