1986 5.0 turns over but won't start

[86_5.0]

I have a 1986 Ford Mustang GT with a 5.0 and a five speed. I replaced the mechanical fan with an electrical unit, and ran a toggle switch into the cockpit. to make a long story short, I left the switch on, drained the battery, caught it the next day, but since i am currently not working and can pretty much walk to everything i need, I Left it dead for about a week. It's happened before, All I have to do is put her on the charger and let the battery charge for about 3 or four hours and she'll start right back up, and so long as I Let it run for 15 to 30 minutes, she'll crank until i manage to leave something else on again. Yesterday, i went outside to start her up, we jumped it off, and it ran fine for about 3 minutes, then the RPM's started to jump up and drop down. It's done this before, and i was Wrapping up the extension cords i used to run the jumper box, and had my friend get into the ca and step on the throttle. He revved it up, taking it to around 4500 RPMs about nine or ten times. All gauges were good, but then she died. We tried to start her agian twice more, but drianed the battery as she refused to fully turn over. We put her back on the charger, let her charge, andcame back later, she started this time, ran for about 20 seconds, then did the same thing. My father came out and said she sounded like she was out of gas, So I Went and Picked up about a Half gallon. Dumped it in her, gas gauge now read that she had a little gas. Tried to start her, she ran for about a minute, then died, Running good at first then repeating the earlier process. I could smell exhaust in the car (she's bad about that sometimes, my pipes terminate about midway between the cockpit and the rear axle.) The guage still reads it has gas, so i thought it might be the ground, i let the car roll back onto flatter ground, then tried agian, started for about 5 seconds, then died, nothing i could do would help (mashing the throttle). Let her be where she was for the rest of the night, took off the charger. Went out to the car this morning and tried to start her up, gas gauge shows about a 16th of a tank, and turned key to acces., heard standard starter warmup/noise (always there, starter is good) then turned her over, she turns over, but won't fire. tried twice more, battery started to drain, then stopped. She's sitting there now, And i need her to run. I've never had anything more than just minor issues (burns a little oil, likes to eat up brake pads a little to quick) out of her, and she was running well last time i drove her. Please help!

[Davescort97]

Welcome to AF!

First things first. Get some more gas in her. It might not be high enough in the tank to be picked up by the strainer. Running the bat clear down could have caused enough oxidation on the plates to short it out. Try another battery. If you let the tank get down to near empty most of the time there probably is moisture condensing in the tank. This is turn will cause rust and plug up the fuel filter. As old as she is it is just good maintenance to change the fuel filter.

[OldSVTGuy]

When you turn the key on, do you hear the fuel pump start up? Maybe bad fuel pressure regulator, bad fuel pump, clogged fuel filter?? Also, could be the distrubor control module as they are known for failing.