i just bought a 90 f150 xlt extended cab long bed, and have been working on getting it running again. it now runs, but whenever i push the brakes in order to shift outta park it stalls out and dies.it is a 5.8l V8 with an Auto transmission 2WD. i have no idea what could be causing this. i need help guys i dont want to have to sell it but if i cant drive it i might as well thank you for the input

 

Disconnect & plug the large vacuum line at the brake booster. Start the engine & press the pedal (it'll take more effort). If it idles normally, buy a booster (used from a JY is fine). If it still stalls, it's an electrical fault related to the brake lights or the harness under the dash near the pedals.

Click my black Bronco in my signature & look thru the Brakes & Hubs album. There's a group of diagrams near the middle that explain the booster.