Re:98 aerostar stalling problem

I didn't know that they made a '98 Aerostar.......... Production stopped in '97.

If it were a 1988 Aerostar, I'd say the TFI module.

Sorry everyone, my bad.I incorrectly stated that it was a 1998.The date of manufacture is 4/95. It is the weirdest thing,after driving for an hour or so it sputters like its running out of gas,but after checking the fuel line by the filter there was no clog but plenty of fuel pressure. I let it sit for awhile then it restarts.In the morning it must be cool enough cause it doesnt act up . But in these lovely arizona afternoons,Yuck! the heat zaps it

The fuel pressure regulator.

Put a pressure gauge on the Schrader valve on the fuel rail and watch it(tape it to the windshield facing in) as you drive and the symptoms return.

It seems to be a common problem on 3.0 & 4.0 Aerostars... underhood temps maybe an issue? It appears to come up more on Aerostars than on Explorers/Rangers & the Taurus/Sable.

Rob

Heat soak, vapor lock.

Even with EFI and the fuel line under pressure form the in-tank pump, if you cook the fuel it will still vaporize in the lines, and the "Low Emissions" gasoline blends with lots of alcohol in them don't help. And if you're at higher altitudes that's a triple whammy.

Some cars have a bypass orifice or a pressure regulator near the engine that continuously circulates some of the fuel back to the tank, and it's supposed to bypass the vapors if it vaporlocks before that point.

But if it vaporlocks past that point, on top of the engine in the fuel rails, you just have to wait for the fuel to cool and liquefy again or purge it out through the injectors.

Make sure that any places the fuel line goes past the exhaust system or other hot points it is well shielded - there may have been factory heat shielding there that a clueless mechanic removed because "It was in the way" or "It got greasy" and they didn't replace it because they weren't thinking.

The test is to wrap a rag around the fuel line in the suspect area and keep it wet with water from a spray bottle, and see if you solve the problem.

It dies, you pop the hood and wet down the fuel lines with a little hand spray bottle full of cool water to condense it, the engine starts right back up - that's proof for me.

That will show where you need to install more permanent forms of heat blocking over the fuel line, like fiberglass pipe-wrap insulation covered with a layer of high-heat aluminum foil style duct-tape as radiant reflective insulation (and oil/grease block).

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And quite possibly the ignition system. The fuel pressure regulator can be a PITA to change on an Aerostar. It's not hard, just inconvenient. A shortened Allen wrench can really help. As often as they go out on an Aero, it's almost a maintenance item.