[AJT1961]

Sounds like it may be time to find a better mechanic. There are any number of problems that could cause these symptoms. If you are a do-it-yourselfer, the place to start is to see if it has any error codes (Autozone and others will do this for you for free) and to test the fuel pressure (1) prior to starting the engine (with the key in the run position), (2) after it is started, (3) while it it running poorly, and (4) for a few minutes after the engine is turned off. If you don't have a fuel pressure gauge, Autozone may have a loaner. Post back the results and I'm certain that someone will be able to help you further.