Ford Repair: 1987 f-150 high idle, vacuum leak, adjustment screw

Question
Hello,I have a 1987 f-150 that idles extremely high? When I unplug the air idle control valve it slows down to normal? So I replaced the valve figuring it was bad and it still idles really high? What could cause this?I am thinking of replacing the tps but dont want to sink a lot of money into the truck unless I know its the problem.I was told it could be a vacuum leak but cant seem to find one? Please help in any way you can and I really appreciate you guys taking time out of your lives to help others.I used to volunteer on this site for small engines and I know how much time it takes.Thanks,
Jason

Answer
High Jason, I was thumbing through the pool and found your question. So I apologize for the wait. I am with your friend, I believe that there is a leak. The fastest way to find a leak is to spray small squirts of carb. cleaner in suspected areas. Until then, if you have not already, turn down the idle with the adjustment screw.