We've been trying to diagnose it for months now. It runs good, except when you apply the brakes and try to accelerate, mostly in reverse and also going forward. Had ECU rebuilt no go. Fuel pressure good. Coil checked & cleaned up. MAP sensor replaced. Three mechanics so far and no go.

 

Welcome to the site.
what happens to the vacuum reading/values when the brakes are applied?

 

Could that particular vehicle have a Hydroboost unit?