94 intermittent crank but no start

The fuel pump relay is the usual culprit. Try swapping the A/C relay with the fuel pump relay. These relays have two sets of contacts. The A/C and fuel pump use different sets of contacts (the A/C uses the normally closed pair, the fuel pump uses the normally open pair) so the unused contacts will be like new.

There are also other relays there for the ignition/computer, could be one of those. Try swapping with other relays of the same part number.

Have someone crank it a bit, then immediately check to see if you have fuel pressure at the fuel injection rail. There is a schraeder valve there for that purpose. There's a safe procedure for doing that somewhere, and the pressure specs, but in general you don't want to do it WHILE cranking or have a cigarette dangling from your lips. It's under pressure and will spray out. If it doesn't, you'll need to figure out why. There's the relay, fuse, and wiring to the pump, the pump, and the fuel pressure regulator. The filter is unlikely as that would cause problems with high fuel flow, not just starting.

Starting requires spark, the proper fuel/air mixture, compression, and timing. The last two are not likely to cause intermittent starting, so focus on the first two. Good luck.

-Paul

Another possibility is the crank sensor. It is a sensor mounted on the front of the engine behind the cranshaft pulley( I think). It senses position of the crankshaft and sends this info to the computer for proper timing and spark. If its defective, the car will not start. Try wiggling the wire connecting to the crank sensor. Do a search on "crank sensor". A bunch of people had problems with it like you. I do not know if there is a way to test it or not.

The crank position sensor affects running as well as starting. I would think it would be dying and running poorly, not just cranking without starting. Here's some good info from Dr. Bob on the crank position sensor:

"The crank position sensor is the hall effect sensor pointing to the front of the crankshaft. The hub behind the front pulley has grooves machined in it, with one groove missing. the sensor reads each of the pulses from the grooves to know exactly how far the crankshaft has turned, and reads the missing groove to re-identify a known position to reference from.

This allows the ignition and fuel injection systems to make sparks and fuel at the right time.

There is a 'limp home' mode, as you have discovered, that allows the engine minimum operating ability so you aren't stranded.

A failed sensor generates an error code, so the diagnosis is fairly straightforward. If you weren't at a Ford dealer, the $200 is the result of not having the right code reader. The sensor takes mere minutes to change."

Here's a description of the problems it causes:

"The crank sensor went out last fall on our '92 XL, too. The car would suddenly die and wouldn't start again. After about 10 minutes, it would start up fine and run like there was nothing wrong (until it would die again, usually days later). Finally, it would run only poorly (the "limp home" mode, I guess)."

I have a 91' 4.0 liter Ford Explorer (176k miles) which is having a similar problem in that it has trouble starting at times. My radiator coolant levels are going down little by little and I have to keep topping it off. I'm suspecting I have a blown head gasket, I pray it's not a crached head! I might tear into that project after the 1st of the year. Is this a symptom of yours too?

The starting problem is most likely the fuel pump relay. It's under the hood on the passenger side of the engine bay, with the fuses. Swap your A/C and Fuel Pump relays, see if that fixes it.

Coolant leaks are commonly caused by the radiator, heater core, and intake manifold gasket. The head gaskets will go if you overheat it, though, so be sure you don't let it go that far. If it's a very slow leak, stop leak should easily fix it.

-Paul