Runs good, but started getting hard starts

The car was stored in a garage for three years and occasionally started. When I pulled the car out of storage it started fine the first several drives.

Not long after I retrieved it this spring I had to replace the starter. I was getting a click with not start.

At the same time that I replaced the starter I cleaned the throttle body.

I think the first reman starter I had was bad. It would make a loud clunking noise half the time.

Replaced it again with a warrantied part.

Now about 1/4 of the time the car will turn over fine but each revolution of the engine sounds like a bang. No firing of the cylinders. I’ll start it again and everything is fine. The car otherwise runs very well, gets great gas mileage.

Leaving the key in the “on” position for a minute beforehand helps to avoid the issue, but it still happens.

Fuel pump? A sensor in the throttle body?

Thanks!