why does my car drop speed or cut off while driving?

what is a scan test please?

THATS A TEST RUN BY A COMPUTER SCANNER FOUND AT MOST SHOPS. TEST WILL READ COMP. CODES TO HELP WITH REPAIR. A MUST ON TODAYS CARS.

I thought you could give me an idea as to why my car was dropping speed/cutting off. You're telling me what to do to find out why it's doing that, that's not really answering my question. Thanks for the input anyway.

WITHOUT SOME TEST RESULTS NO WAY I CAN ANSWER YOU! COULD BE A BUNCH OF THINGS. IF I COULD TEST DRIVE YOUR CAR, MAYBE I COULD TELL YOU MORE. BUT CAN'T SO, NEXT TIME YOU FEEL BAD, EMAIL THE DOCTOR AND ASK WHAT IS WRONG. BUT THEN HE SHOULD BE SMARTER THAN I AM.

Thank you