I recently was driving my car to work when it started acting up a little. I just filled the gas tank and whenever I was going above 40MPH, when I let off the gas the car shook (not the wheel). I live close to work so I drove the rest of the way and it continued. I couldn’t get it diagnosed until I got paid, but I needed to go to work again. On a full tank, I drove roughly 30 miles. When I went to leave work my car would not start but was cranking. I had my battery checked and it was more than fine. I think it’s either the fuel pump or timing. What should I check first to diagnose it? I’m new to working on cars and have a very small budget so I’m trying to do as much as I can on my own.