I recently bought a 95 cherokee and it has a very small transmission liquid leak. My concern is about the acceleration in reverse. Last night I was driving it and when I put the auto in reverse and accelerate the engine shut off. Today, after changing the mass sensor for a new one, I can't even put the handle in reverse because it shuts off without even accelerating. A mechanic told me it wasn't a transmission fault. What do you think? What else should I try? Everything else (mechanic) is perfect. It even has a new battery (just in case).