Is this weird...or normal?

[Asapatrick]

Hello,
I have a 1997 4x4 CrewCab, auto trans, 270K miles....had it for about two months.

This last weekend I noteiced something I had not before while going down a long grade....5-6 miles, coasting most of the way. It was icy conditions and 22 degrees. When I would reapply the throttle, there would be this kind of resistence, felt sort of like a compression brake that would slow the truck down until I pushed far enough on the throttle to begin to rev the engine again. I sensed it was happening when the torque converter was trying to re-engage. I do not know the history of the truck....is that behavior normal, is it possible the way an aftermarket torque converter works....or is mine about to blow? Btw....otherwise it seems to shift perfectly.

Thanks in advance,

Shannon Flanagan

[Diesel_brad]

Could of been the Exhaust Back pressure Valve was closes. And until you build enough boost it will stay closed. I kinda acts like and exhaust brake when it is closed

[Asapatrick]

Thanks Brad for responding. Does that mean the "exhuast back pressure valve" is malfunctioning, or that some other issue is at play...like a turbo that doesn't boost enough?

Shannon

[JSchuricht]

There's a bunch of unknown's there. 22° is cold enough for the valve to close but it should be open if your up to temperature. In the factory configuration it only closes to help with warmup. Is your thermostat working and do you have any aftermarket programming? Also look under the hood to see if there is any extra wires running to the valve, many people like to put it on a switch to use it as a exhaust brake.