1999 Ranger 2.5L engine. When I turn on the A/C,does fine until you accelerate, then the air stops blowing through the vents,then when you ease up on the accelerator,the air returns to the vents.I think it has something to do with the vacuum lines or vacuum system.Please give me some ideas. Thanks

 

Look for cracks or melted areas in the vacuum line running near the PS Exhaust manifold to the AC box. Then inspect the vacuum reservoir and its check valve. Check for leaking hoses or vac servos under the dash.