2004 Silverado won't go over 67mph

[fireman21]

:huh:My 2004 2500HD Silverado Duramax 6.6 4X4 will accellerate to 67 mph with no problem. At 67 it loses throttle response but will stay at 67. At around 67, if I push on the pedal, as if I would want to pass someone, it shifts to a lower gear but no throttle. It actually slows down because of the lower gear. At that point after I slow down or stop, when I try to accellerate again it hesitates after shifting gears, kind of spudders at first and slowly gains speed. Anyone have any thoughts on this?

[tac]

Is the 67 max speed the same uphill as downhill?

I can't say if it's the same issue, but I had the same experience with an old Chevy pickup. For me, it was the fuel line. I had been hauling loads of mulch for a week or so, and somehow I much have left the gas cap open but under the panel - and it had sucked in enough mulch-dust that it had the fuel filter clogged like it was drinking through a cocktail straw. A new fuel filter gave it all its pep back.

Diesels are even more picky about their fuel, so it's at least something to consider.

[fireman21]

(11-05-2010 03:02 AM)tac Wrote:  Is the 67 max speed the same uphill as downhill?

I can't say if it's the same issue, but I had the same experience with an old Chevy pickup. For me, it was the fuel line. I had been hauling loads of mulch for a week or so, and somehow I much have left the gas cap open but under the panel - and it had sucked in enough mulch-dust that it had the fuel filter clogged like it was drinking through a cocktail straw. A new fuel filter gave it all its pep back.

Diesels are even more picky about their fuel, so it's at least something to consider.

Thanks for replying. But, I ready tried some things.
Though it seems the problem has been resolved. I'm not sure what fixed it but it seems to be running fine now.

First thing I did was along your lines. I changed the fuel filter thinking maybe I picked up some bad fuel and it was also about time to change it anyway. I also changed the air cleaner. It was dirty but the indicater was not showing in the red. After that I took it for a test drive but it was still doing it.

Second, someone metioned to me that they were having a problem with thier over-drive/trailering switch on the shifter. The indicater lights for the over-drive "off" nor the trailering mode lights were on, but I cycled the switch anyway. The transmission seemed to operate correctly.

I have been out on the highway a few times now with no problems. I guess the switch is what fixed it but I'm not sure if it just needed a little more time for the fuel/air to get back to a regular flow because I didn't give it much of a test after the first try.

Thanks again.