Grand Am, Erratice hard starting

2004 Grand Am. 3.4. About a month ago it started starting hard. Had to crank it several seconds to get it started. Also, it had frequent erratic idling etc. Mechanic said He thought it was Fuel pump because it showed slightly low pressure, but wasn't 100% sure. I had the Fuel pressure regulator replaced in the last year, plus it wasn't spewing fuel out the top like they do when they go bad.
Okay, here is where it gets weird, two days ago, it started acting perfect again. Fired right up every time. Only twice did it take 3 or for turns of the motor before it fired up. I drove it 500 miles yesterday and it ran perfect. It started up fine this morning too. The gas mileage checked out at 30 mpg.
What in the name of freedom could be plaguing my car? I doubt its the fuel pump.

Have you read the codes? Even if there's no check-engine light, there may still be stored codes. If you don't have a scanner/reader, many of the parts stores (autozone, advanceauto) will read them for you for free. Make sure you write them down. In the mean time, 30 mpg is pretty good; lots of things are working just fine. Maybe it was just some "bad" gas.

At one time there was a "Random Cylinder Misfire". Mechanic said that could be because it wasn't getting enough fuel. I've replaced fuel filter, ran good cleaner through the system, etc. Gotta remember that this has been going on for a month. It isn't bad fuel.

try cleaning injectors