ok for the last month when i start my truck it would start hard then the starter went out fixed that still doing the same thing now around the same time maybe a little more then a month ago when i start my truck it will jump to 1000 rpm and not idle down so i replaced the iac and did the relearn on it seem to help for a week now fast forward to last couple of weeeks if i start my truck in teh morning it starts rough jumps up to 1000 rpm and wont go down if i drive like that it shifts hard i mean throws me into the steering colum hard if i pull over and shut it off then start again it wont do it and run and shift just fine
but if i start it again after that it does the shifting hard and rough and high idle and wont come down to teh 600 rpm where it should be
when im driving down the highway and it started hard and idles at 1000 rpm at idle i will try to acclerate to highway speeds it will rev up really high then shift so damn hard if i let off the throttle before it reaches 3000 rpm it shifts a little smother then i ease back into it still does it
but if i pull over shut it off then it goes back to where it should be no shift problems at all and yes it is affecting my gas milage im almost afraid to tow my 18 foot camper anymore
the engine is a 6.0 l v8 chevy silverado 2500hd
i replaced the plugs and gapped them properly and also replaced all the plug wires iac valve
so if this problem persists and i cant figure it out i am going to let the engine blow up and leave it on the side of the road
also all the temp and idot gauges read normal all while this problem goes on
any ideas thanks

 

Well replaced my tps and it seems to be idling normal now but we will see when I leave Sunday for my 200 mile trip back to work for the week

 

Look into replacing your MAF too.

The TPS and MAF work together to tell your transmission when to shift.

 

it seems to be working now pretty well after i did plugs and wires
its been awhile since i have been on here