out of the blue my trans was not grabbing and engine reved up to 3-4 grand then as I laid off pedel it started to work again but did it again I replaced the p0715 error code speed vvs but did fix it the mechanic said any help

 

Year, engine, sub-model, mileage?

 

Could be a number of things. Clogged fuel injector, failing tranny, or even the tps sensor (which is known to do what you mentioned). I'd try testing the tps first with a multimeter and seeing if its within spec. Then dump some fuel injector cleaner in there for good measure.