1999 Ford Explorer Engine jumps and loses power

1999 FORD EXPLORER
186,000 MILES • 6 CYL • 2WD • MANUAL
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SINCITYVIPER
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My 1999 explorer has a problem. I live in las Vegas and the problem only happens with is get hot (usually in the summer when temps are over 100) or if I drive it for longer than an hour in colder temps. About 30 minutes into driving almost on the clock when it is over 100 degrees, my engine will start jumping and hesitating. From a stop as I push in the gas, it will jump a lot, and or will not go over 1500 RPMs for a second or two then jump up with alot of power, then drop again. The harder I press the gas the more it hesitates and jumps. I have to drive in lower gears at lower RPMs to "mask" the jumping. It does not turn off or die. And if i park it for 10 minutes it will stop for a few minutes then start back up once driving. If it cools down completely it will take about 30 minutes again. If I push in the clutch, my engine will rev up in RPMs no problem however, trying to move the truck the problem occurs. My check engine light is off, I had the O2 sensors replaced, because the mechanic I took it to said that would fix it. And I replaced the MAF sensor about 30,000 miles ago and it was happening before then. As long as the problem is not happening, I do not smell gas. But if the problem is, then I smell gas.

Also as the engine warms up, there is a lot wining or humming sound come from the engine during idle. Even if the problem is not happening.

If I could stop the sound coming from my engine and the jumping/hesitation problem that would be excellent.
Jun 29, 2010 at 9:57 AM
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JACOBANDNICKOLAS
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If you smell gas when it is happening, I need you to check two things. First, you need to make sure the fuel pressure regulator is good. Also, have you ever checked the crank sensor?
Dec 21, 2020 at 3:24 AM
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SINCITYVIPER
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[quote:5f09fd7168="Jacobandnickolas"]If you smell gas when it is happening, I need you to check two things. First, you need to make sure the fuel pressure regulator is good. Also, have you ever checked the crank sensor?[/quote:5f09fd7168]

No I have not check the crank sensor. I will take a look at that. Thanks

What about the loud humming sound that comes from the engine at idle?
Dec 21, 2020 at 3:24 AM
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JACOBANDNICKOLAS
  • ASE Certified Mechanic
  • 110,219 POSTS
  • ASE Certified Mechanic
Check the accessories that are run by the belt, water pump, PS pump, alt... Remove the belt and start the engine to see if the sound is gone. NOTE: Only run the engine for a few seconds to see if the noise is gone. It will overheat.
Dec 21, 2020 at 3:24 AM
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