high idleing 87 gmc S15

[Chip_067]

I have a 87 gmc with a 2.8
Runs fine when first started but after running about 15 minutes in hot weather the throttle will start to stick. You can romp on it and it will idle down, but only so many times. Eventually it will stay at high idle (at least 2000 rpms) till shut off and cooled down. Check engine light will come on after it starts sticking too,tried retreiving code but showed nothing. Have removed cables and lubed,replaced tps,and o2 sensor,and sprayed with throttle body cleaner. Have also sprayed around intake,throttle body lookin for leaks.Hoses look fine too. Sorry about the book, Just trying to give as much info as possible. Any help/guesses would be appreciated, Chip

[fast68]

take and remove the IAC motor form the TBI unit and lcena off the tip of it and also the hole in the TBI unit for it with carb cleaner and then see how it does, also have the TPS tested it may need adjusted and it is very tricky to adjust these, it probably is worn out most likely, if there evne is a problem with it