I have also installed an 89 FPR on my 86 van & it was not enough to make a noticeable difference. I also tried different brands of gasoline & that didn't seem to make much difference either. As a result I believe gasoline with a high boiling point is a thing of the past. Ventilating the engine compartment did the trick for me. To test yours, you may want to lift the engine access when making your stops during the day. If this eliminates your starting issues, then your problem is heat soak. Tim

PS: As a general rule I don't believe in, nor do I use automotive additives. Some may work, but I think most of them are a waste of money. Just my $.02.