engine racing

MITSUBISHI
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MIGHTYMAX
  • MEMBER
  • 2 POSTS
1989 Mitsubishi Mighty Max: 38,000 miles. The truck starts normally, but soon thereafter, the engine starts race as if I was depressing the gas pedal. This happens when it is in neutral as well as in gear. When it is in gear during this time, the car accelerates by itself. After a couple of minutes or less, the idle/engine speed returns to normal and the truck operates fine. Any ideas?
Aug 12, 2006 at 1:17 AM
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SERVICE WRITER
  • ✓Experienced Mechanic
  • 9,123 POSTS
I can't give specifics, but can give some theory.

The truck is started cold, it wants more gas to get to temperature,( the higher idle). The engine gets to temperature and the idle returns to normal.

Sounds like somthing that is engine temperature related (coolant temp sensor for example) that is giving false data, saying that it is colder than it really is and suppling more fuel.

I may be telling more than I know, so dan't take it to the bank.
Aug 12, 2006 at 1:29 AM
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