What would you look for if the car wont stay running unless you have your foot on the throttle?

Have you checked the fuel pump for any blockage? The car isnt getting any gas unless u manually pump it by pressing the pedal.. So start there
Sometimes when a engine requires excessive revving and throttle to stay afloat its a fuel supply problem. A clogged filter for example can be overcome with excessive throttle that drives the fuel pressure up enough to force it through, but it will barely trickle at idle and stall.

Usually the dead give away for fuel pump is when someone complains they have to floor it as soon as it turns over or it will die right away.

You have a single fuel injector in it right. Try right at the end of the gas pedal cable at the engine there is an electrical plug and a little device that goes around in a circle when the gas is mashed. That is the throttle position sensor. Try unplugging that and if there is no difference in the revving then the throttle position sensor is out. If that is not the problem, then plug your engine into a an onboard diagnostic reader. 85 is an obd1.

Computers rarely fail. The diagnostic would not show anything wrong unless a trouble code is set UNLESS the diagnostic used live data vieew. Most shops dont do that . So at what RPM does it not die? How many miles are on it? Ford uses something called an idle air speed motor. They are prone to fouling.

isame problem its happen to me, check battery voltage and probably air leak too.

replace the throttle positioning sensor on the throttle body. It will need to be reset upon replacing it so have a qualified mechcanic do it for you

try and clean the throttle body and throttle plate and the idle air contol valve

It sounds like the throttle position sensor

check idle air control motor or could simply be throttle plate very dirty

Withoutknowing if the check engine light is on it could be a variety of things including but not limited to the o2 sensor, throttle positioning sensor, and the MAF and MAP sensors. Best diagnosed by using an OBDII scanner to scan for codes. If no codes are present I would then check for the pressure coming from the fuel pump to make sure it is still functioning.

What you have is PROBABLY a bad Idle Air Control stepper motor... if the car stays running with your foot on the gas, and only dies when you let your foot OFF the gas... or if it dies when you shift (again, cause you foot is off the gas) that is definitely the problem. The stepper motors are kind of pricey (over $300) at the dealership, but you should be able to get one from an auto parts store for 150 or so. easy as heck to replace, it has three 8MM bolts into the throttle body, just unplug it, unscrew the bolts, and put the new one in... just be sure to be careful with the new o-ring... DON'T LOSE IT! :)

Good luck!