Today my truck left me on the shoulder driving 8-10 MPH. It won't rev past 1,500 and then only at half throttle. When I am running 1,500 rpm and mash it, the engine drops to a constant 1,000 rpm. I have to let it idle and then ease into it again to get it up to 1,500 again. Then if I push the throttle a little farther, it starts to accelerate and then drops off to 1,000 rpm again. What has happened?

Do you have a code reader?

Do you have a tuner? Edge, Predator etc?

Are you sure it is 1500rpm and not 2000 rpm?

Did you try shutting the truck off for 5 minutes and driving it again?

Truck is all OEM. I have shut the truck off and restarted it several times today. It hasn't changed anything. It will not rev to 2,000 or even close. I left the truck off for 30 minutes and also let it idle for an hour. Still no change. The SES light is on but I haven't read the code. I will try to get a reader tomorrow.

Take it to the dealer. Something is very wrong.

How many miles? How long since you changed your fuel filter? Sounds like mine did when the injectors went south! :o:

I changed my filter today and it didn't help anything. It was only a few days ago I did a routine filter change. I have 41,000 miles without prior problems.

Sounds like a shorted out wire in the FICM. There's a TSB on it. You can fix it yourself as was suggested on here a few weeks ago. Try this
http://www.dieselplace.com/forum/showthread.php?t=36956&page=2&highlight=FICM

I put a scan tool on it today and found P0087. No other codes. I cleared the code and the problem is still the same. It starts fine, idles fine, revs to 1,500 rpm fine, and holds a constant 1,000 rpm when I mash it. Once I mash it, it drops to 1,000 and won't budge until I release and re-accelerate at which time it goes back to 1,500, etc. Does anybody have another idea to try? Is is possible that the fuel filter can cause this?

The same thing happened to me. No codes, no lights, just limp it in. Shut the engine off and it would run fine for 3, 4, sometimes 5 miles but would drop rpm to 2000 rpm and into limp mode again. My fuel filter only had 7000 miles on it but had the stealer put a guage on the filter housing for vacuum restriction and sure enough, pulling a 6. Supposed to be 2-3 psi and replace over 5. Problem solved!