1993 F159 5.0 problem

I had a similar issue with my 1990 model. I took apart the air intake hoses and sprayed cleaner directly into the intake chambers. At the advice of the guy at the parts store, I used brake cleaner instead of carburetor cleaner. It burned clean, and did the job well. You’ll need to keep one hand on the throttle to keep it from stalling while spraying. If you haven’t already done this you might give it a try. It’s a cheap solution and only took maybe 30 min.

I had a similar problem with my 1990 model. At the advice of the guy at the parts store I took apart the air intake hoses and sprayed brake clean directly into the intake chambers while it was running. You could see it was dirty and funky, but after a full can it was clean and ran smooth. If you haven’t done that yet you might give that a try.