BigJ23

I have a 2000 5.4L V8 Fx2 automatic F-150. The only mods I have is a single in dual out flowmaster exhaust. I started a new job and now have to get on the interstate everyday for about a 20 mile drive. Since then I've noticed that my truck starts up with no problems, drives and shifts gears with no problems, but as I'm getting off the highway and it starts to down shift right when I pull to a stop the truck stays ideld really high for about a sec or two then it drops to its normal 500-600 rpms. It doesnt do this while I'm driving on normal streets but only when i'm getting off the highway! I only go about 65-75 when I'm on the highway. Could this be a sign of a transmission problem or something else? I have about 161,000 miles and was thinking of maybe a transmission flush but was concerned that could hurt also. Please any and all advice is greatly appreciated!!!

BigJ23

Any thoughts anyone???

greenheadkiller98

Sounds like a vaccum leak to me

BigJ23

Thanks for the input. How can I find out for sure and how to fix???

greenheadkiller98

Check all the vaccum lines visually, if you cant find it use a tester (i forgot the specific name of the the device used to test it sorry)

BigJ23

If I find the leak, how much will it cost to fix and how big of a job will it be?

greenheadkiller98

Shouldnt be too much, you could do it yourself and it would cost as much as the hose that is leaking (if thats the problem) wich isnt much money. And you could probably do it yourself