Rough idle on warm start up (20 minutes), 87 7MGTE

[Bru]

This engine heat soak issue continues to bug me. I did some research on the web and found out that heat soak maximum temperature occurs between 30 and 40 minutes after shutdown. Another Web site about boat engines recommended running the engine for a few minutes before shutting down to minimize the problem. Opening up the hood would also help but that's not always possible in public parking lot. Winter formulated gas between September and April has a lower boiling point than summer gas along with containing 10 percent alcohol, which exacerbates the problem year-round. Living in Central Florida doesn't help matters either. We all know how hot the Supra engine runs. I'm going to try a trick next time and jumper the B+ and Fp on the diagnostic block and let the fuel pump run for a minute to flush any vapor out of the rail before I try to start the engine. There is one station in town that sells old-fashioned pure gasoline at a premium price. I may try a few gallons of that if I can't find out what's going on. If that doesn’t work, I may have to swap out the igniter and /or the cam position sensor to rule those out.