Something strange has happened twice to my truck. I have a 2000 4.6 with about 4500 miles. Mods include AIRAID and FLWMASTER 40 SERIES. First time it happened was about a week ago, second time this morning. I drove about 12 miles to work this morning, I shifted to Park and the engine, all by itself, went all the way up to 2500 RPM with a sound like the belt was rubbing on the pulleys. Then down to normal idle and then up and down up to about 1300 RPM. I shifted back to Drive then to Neutral, gave it a couple good shots of gas and it went back to normal idle. The temperature outside was about 20 degrees. I got the truck back in September and it never did this before. Blame it on the cold?? All the experts, please help. Thanks!!!

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2000 4.6 XLT Ext. Cab Silver

So Far
- ARE Z-series Color Matched Cap (for the Rotties...)
- Flowmaster 40 Series with Edelbrock Oval Tips
- Airaid Intake System
- Sony, Lanzar, Profile, Polk, Kenwood, 500W Sound System
- Closer to the Ground 3" front and & 5" rear
- Clear Corner Lenses

Future
- 20" Rims with 275/35/20 Tires
- Street Scene Color Matched Mirrors
- SVT Bumber Cover
- Supercharger (way down the road)

 

It happens when the defroster is in the on position on my truck. Try turning the defog off and see what happens it should be OK.

TD

 

If it happens when the defroster is on as in
AH-64MTP's truck then the AC compressor is on causing the engine to rev higher.

Hobbit

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99 XLT,4.6L Auto,4X4,tow pkge,Factory Side Steps and Mudflaps, K&N filter,BugflectorII, Amazon Green/Silver, Pace Edwards Rolltop Cover, I got my Superchip, waiting to get jumper problem fixed and chip installed.