First of all, a little about the car...

03 Coupe 6MT
110k
It is stored in Utah about 10 1/2 months per year.

My wife and I live abroad for work but we kept the G so that we'd have something to drive while we are back home visiting. So it doesn't get driven much. On our last trip back, I took the battery off of the trickle charger and it fired right up. It ran great for a week while I was there. Soon after I left, my wife said it would fail to start sporadically. It would just turn over. She'd try a few times and eventually it would fire up like nothing was wrong. She said it got worse as the week went on. She left and it went back in storage. We are preparing for our next trip back and I really don't want to spend the whole time diagnosing the problem. Are there any common issues with these cars that would cause this? Fuel pump, some ignition problem? Any ideas?

 

It is very difficult to diagnose the problem with the information provided.
Vehicles in general do not start for very simple reasons. Fuel, Spark, compression, even timing in some vehicles etc..
I dont know of issues with the g35 that involve the fuel pump but some people have had to change theirs. more information will get someone to help you more.

 

Update: The culprit was a cheap eBay key. it worked fine for years but recently failed to transmit the correct code to start the car at times. Hence the intermittent starting issues. I tossed it and only use the original key now. Problem solved.