My '96 GMC K2500 Suburban had a similar issue.
It would start good for a period of time then one day it would just spin without catching. It might start in 5 minutes or five hours or, maybe, days.
It got worse maybe not starting every morning for two weeks. I thought rain in the distributor cap. Went and got an Accel aftermarket cap.
Then put new thermostat in since temp gauge was not coming up to center of gauge. That's when I noticed a sending unit on or near the thermostat housing. Just a small one. It was busted at the base. Went to Advanced Auto and got a new one.
Put these items on and haven't had a problem since before I replaced them.
It runs better and starts like a new one.
I don't know what item being replaced fixed the problem or if all three contributed towards fixing my Surburban.
Just something for you to check. Good Luck!

 

We have a 2007 LTZ. We began having problems at 150,000 miles. The engine light came on, stabilitrack sensor came on and idling high. We went to the mechanic and he said that a lifter needed to be replaced.


We went ahead and changed all of the lifters and the oil sensor. (not a mechanic at all, but learning what some parts are called) It worked great for a month then the oil pressure dropped to 20 and the car told us to stop and turn off the engine. We took back to mechanic and he changed the oil sensor again, dropped the oil pan, and changed the oil. It worked for 2 days and then the engine light came on again. Test showed that we needed to replace cam shaft position sensor. We took back to the mechanic. He changed that.


The next morning when I started it, it had trouble starting. It would turn a few times then start. The engine light came on again and said that it was still the cam shaft position sensor. WE took back to the mechanic and he cannot figure out what is wrong.