I replaced the throttle position sensor on my '93 F150 302. Fixed the hesitation problem but now it idles too fast. I set the TPS according the instructions and i'm sure it's right. In the morning, the truck idles up when it's cold like it should and then it drops down. trouble is, it doesn't drop down enough. I could drive 15 miles an hour if i let it go. The throttle body is closing completely...i checked that. If you unhook the IAC valve, the truck will idle down real nice but the trouble is it won't idle fast when it's cold without the IAC valve hooked up. Sounds to me like the IAC valve is working like it should but is getting some kind of signal making it idle too fast. Or do I have a vacuum leak? has anyone tried using propane to find vacuum leaks? Thanks in advance, Kent