How can I tell if the timing chain is bad on my g5 gt?

Timing chain would make some noise, but I don't think it would be the timing chain since they usually last over 100,000 miles. And you would have some timing issues that the cam sensor & the variable timing solenoid would pick up. May just need to run some injection cleaner threw a few times, or it may need a tune-up.

Thank you. Someone had told me that it needed a new timing chain since all it does is hesitate to start even though the first code to come up was the crankshaft sensor which I paid to be replaced. But he said he would have to take the engine apart to be sure and that would cost about $1000. A few other people mechanics had told me that it could be it just needs a tune-up with new plugs and coils.

Could be, just find someone good.