Did you use the SeaFoam before? At a shop that I managed, we had some trouble with SeaFoam... running it through the vacuum system. It was causing high idle/ or stalling problems, because of the SeaFoam deteriorating the vacuum hoses and clogging them.

Check the vacuum system, even if you didn't use it before.

And I also agree with NeverBX :cheers: ...sticking throttle, among other preliminary checks.