Engine low power?

2000 FORD EXPLORER
120,000 MILES • 6 CYL • 2WD • AUTOMATIC
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JTL5729
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  • 1 POST
My problem has been going on for nearly a year now. It doesn't seem to be getting any worse, but at the same time, no better. My Explorer has no "pick up" after idling, even for a brief time, like for a red light. After the car "gets going" its fine. But at every stop, it struggles each time to gain momentum. The only temporary "cure" is to turn the car off. If I am at a red light, and turn the car off, just briefly, the car is fine temporarily.
It is beyond aggravating, and I have since had to replace the starter, but the mechanic I took it to couldn't figure out what else was wrong. In failed attempts to fix the problem, I have had the air filter changed, the fuel filter, and had the fuel injectors cleaned out.
Any help greatly appreciated.
Oct 21, 2010 at 10:47 PM
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CARADIODOC
  • CAR REPAIR CONTRIBUTOR
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Hi jtl5729. Welcome to the forum. This is going to require a live human being to do the troubleshooting, but I can provide a suggestion based on my previous experience with my '88 Grand Caravan. The engine ran fine that faster I drove, and would die as soon as I let off the gas. It only happened on the two hottest days of summer, then was fine until six months later. Turned out to be a plugged pickup screen inside the tank.

This could happen to any vehicle with a fuel pressure regulator with a vacuum hose attached to it. Two forces act on a molecule of fuel about to squirt through an injector. They are manifold vacuum and fuel pressure. During coasting, vacuum goes way up so the pressure regulator drops fuel pressure so the total of the two forces remains constant. That prevents an overly-rich condition during coasting. As I figured out later, during coasting, since pressure drops, it is much easier for the fuel to go through the regulator and back to the tank. (This is called a "return" system). Easier fuel flow through the regulator means the pump has to move a larger volume of fuel. THAT'S when the partially plugged screen restricts the flow so pressure drops too much. After sitting for less than a minute with the engine stalled, enough junk floated away from the screen that the engine could be restarted.

Now that the problem is understood, there are two things you can try to see if this is your problem too. Remove the vacuum hose from the regulator, (if it has one), and plug it, then see if the problem is still there. You might see black smoke from the exhaust from it running too rich but it should run better. You can also install a fuel pressure gauge and hook it under a wiper arm so you can watch it while driving. Watch for the pressure dropping while you're waiting for that stop light.

caradiodoc
Oct 21, 2010 at 11:55 PM
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