I have F150 1991,I had problem with starting then I change key cylinder, everything looks fine, it start promptly, but car will power out or die sometime. After couple days of driving I notice that car will lost power by itself when I turn the wheel to left or right. I can't find out what wrong. Could someone guide me what is a problem?

 

Mine did that. I cleaned the throttle body with some throttle body cleaner, and it stopped. Dont ask me why.. but it did. My truck would stall out when I turned hard left and this is when I worked at a car shop. I talked to one of the guys and he told me to clean the throttle body, it fixed it. Im not saying that is your problem, but it cant hurt to try it.

 

before I changed my key cylinder, I also change valve cover too, and use brake cleaner to clean throttle body but not quite good cleaning. What did you use to clean throttle body? As you said, that might be my problem too, thank you for advice, I'll try to clean throttle body real good again this time.