When I first start the truck in the morning, everything is fine. Starts just fine, idles right at about 800 rpm, no lope, no smoke, it's picture perfect. I can tap the accelerator and it speeds up and drops right back to the same rpm, no problem. A few minutes into the drive, everything is still fine. As I drive more, the idle speed increases to the point where after about 25-30 minutes (after driving down the highway) that it will idle at 1300-1500 rpm. A quick rap on the accelerator may help it drop a little, but not much. When I leave work at the end of the day, it once again starts out just fine at about 800 rpm. The longer I drive, the faster the idle speed gets.

I tried spraying the linkages with degreaser and lubricant and kept working it as I sprayed it, and it was fine for a few days, then it started doing the same thing all over again.

Anyone have an idea of what's wrong? The truck has about 190k miles on it right now if that matters. I looked for a return spring that may be weakened, but I didn't see anything other than the large coil spring on the linkage near the lift pump, and I have a hard time believing a spring that large would get that weak that it couldn't pull the throttle back into position. But I suppose anything is possible. I was thinking I might just go get a generic throttle return spring off a carburetor and fasten it up to see if it helps.

Any help would be greatly appreciated. It's getting a little frustrating and dangerous trying to drive thru town with the idle that high.

 

Have you had the recall on the throttle cable done yet, it will fray inside and toward the end and stick.

 

Try dropping the idle down. My 24v did this. I drove it for about 4 months after the conversion with no issues, then it started doing exactly what you are saying. It kept getting higher. I thought something in the governor was hooped. I got the truck warm to where it would idle too high, and set it to 900 rpm. Everything has been good since then.

 

Ocmechanx, no, I have not replaced the throttle cable. I did replace the connector on the end of the cable to the linkage a few years ago. I did not get a recall notice about replacing the cable, should I have received one? Which cable are you referring to?

Tate, I thought about doing that, but if I adjust it down so the high idle speed is at the right rpm, then it will be too low when I first start driving the truck and stall. I would basically have to cut my rpm in half to make it "normal" and it'd be almost to zero when it was first started. I don't think this will work for me.

 

Not always.
Check if the recall has been performed here, you will need your VIN.
http://www.dodge.com/webselfservice/...m('R')

 

Your fuel tank vent isn't plugged so that the tank is pressuring up and back pressuring the fuel system causing it to idle higher.
Had this happen on a big truck with a cummins so just a thought.

 

Not true. When my truck was doing this, it would start at about 850 RPM, and climb to 1300-1500. I dropped it down to 900 hot, and starts at 750 cold. Give it a shot. Worse that happens is that you raise it up again.