Timing belt

I am sure they would see no problem. Things rarely screwup when the mechanic is looking at it. The car tries to make you look like an idiot.

Look, there is no easy solution. Why? Because the problem doesn't manifest itself as the right time. What you need to do is either let it get worse or try doing some troubleshooting on your own.

For instance, when you get to the point where it does not want to start. Don't alter anything than hitting the to start it. Don't touch the pedal, etc.

During this time, with assistance, check to see if there is good spark at the plugs. There could be an intermittent problem with one of the sensors or the fuel pressure regulator could be bad. Heck, it could be the ignition switch. I favor the fuel pressure regulator.