I have a 1998 Chevy Z71. I have always noticed that when going down the
highway and I let off the accelerator, it takes a second for the engine to
idle down and begin slowing the truck. (I was told this was common). This
"let down" had a vacuum feel to it.
The problem is that for the last year or so it doesn't want to idle down,
i.e., I have to apply the brakes to get the engine to start "letting down"
and then the engine doesn't help slowing the truck much. Obviously this is
a pain when going downhill or exiting on a downhill offramp.
Any help is much appreciated.