1999 Mitsubishi Montero idles too high

Tiny
2CARPROS-ARCHIVES
  • MEMBER
  • 1999 MITSUBISHI MONTERO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 109,210 MILES
1999 Mitsubishi Montero mileage: 109,210. My truck was working fine but due for a major tune up. I took my truck to a local shop for a tune up. When I picked up my truck it drove fine for about twenty minutes, but when I came to a stop I noticed my truck's idle was very high and fluctuating from 2500 to 3500 RPMs. The idle should be between 500 and 1500 RPMs ideal is at 750 according to my manual. I took it back to them and they adjusted the throttle. I drove off again and in twenty minutes my idle was at 4500 RPMs. I found a mechanic at 6:30 PM on Saturday, Memorial day weekend, he said the distributor was anywhere from 45 to 90 degrees out of position and for the adjustments they made to my throttle they should have been fired. I brought my truck back in today and again they did the timing and adjusted the throttle. They hooked it up to the diagnostic and nothing came up as a problem. After thirty minutes of driving it out of the shop my truck's idle was back to fluctuating between 2500 and 3500 RPMs. Any ides what they could have done during the major tune up to cause this? As the problem was not there before the major tune up? Vacuum hose? Throttle sensor? It has to be something that builds up pressure since it only starts acting up after twenty to thirty minutes of driving. I am baffled I really hope you can help.
Do you
have the same problem?
Yes
No
Wednesday, November 10th, 2010 AT 6:34 PM

1 Reply

Tiny
2CARPROS-ARCHIVES
  • MEMBER
If a strong fuel injection cleaner was used on the fuel system it may have burned out the Oxygen sensor. Please understand that Oxygen sensors do fail and if it was close to failing at the time a fuel injection cleaner was used, the cleaner would have been enough to push it over the hill. Replacing the Oxygen sensor in this case should remedy your problem.
Was this
answer
helpful?
Yes
No
Wednesday, November 10th, 2010 AT 6:40 PM

Please login or register to post a reply.

Recommended Guides