Hey Gang,
Need a little help. My daily diver (92 F-250 7.3l) finaly gave up the ghost. I had 427,000 great miles out of it. The engine lost a piston. Someday I will stick a motor in it.
I bought a very nice 1995 F-250 5.8,C-6 auto, 52,000 miles and not a scratch on it anywhere. It belonged to a friend who ownes a plumbing co. and is semi-retired hence the low miles. He bought a new truck in January and this one has been sitting.
I have a few questions for you.

1.) The idle speed is about 1800 in park or neutral. It will go down in anywhere from 5 mins to 1 hour. I cannot find any predictabillity in when it will calm down. When it does clam down it stays until the next restart. warm or cold makes no difference. (well it seems to calm down sooner if the engine is warm)
The check engine light came on a few times at first but has been staying off.
Here are the things I have done so far.

Search this forum for similar problems and follow advice given.

Removed, cleaned, and verified proper opperation of Idle speed contoller.
It was nice and clean and the ohm tests were good.
When I unplug it the idle will return to slightly below normal idle speed.

Checked entire engine and HVAC system for vacuum leaks.

I repared a bad one going to the throttle body on the drivers (same side as idle contol) side.
I repaired another one going to recic. door on ac (pass side firewall)

Read trouble codes using a paper clip and mil.
I had tons of codes. I missed some of them but I saw 12,13,18, and maybe 17

Replaced coolant temp sensor (the 2 prong one for the computer)

Replaced air filter, breather filter, PCV valve, thermostat, rad. cap, and all belts and hoses.

Complete fluid service including oil,filter, transmission flush, and rear end service.

I have unhooked the battery to let the computer reset. After I did the above work the idle was still fast.

I will report codes after the reset and a test drive.

2.)
The rear tank had about 1/2 tank of fuel in it. It will almost run on it.
Should I fill it up and try to burn it or drain the tank, add fresh fuel and go from there?
The fuel smells old.
The front tank had about 1/8 of a tank but ran fine after filling it with fresh fuel.
I will change the filter when I get good fuel in both tanks.

3.) I have only driven about 100 miles and it has used a full (front) tank of fuel. Is this all it is going to do?

4.) Need to emission test for inspection sticker. I will drive another tank or so of fuel thru it and try t get idle under control.

5.) Did ford offer a C-6 in 95? I can find no evidence of overdrive. It has 1 drive position and no button like my E40d. If so that is great for longevity.

6.) Sorry this is so long. Thanks in advance for your help guys.

Justin