I acquired a 2003 H2 about 2 months ago and went through it from top to bottom. Think about $2,000 into it replacing all sensors, gaskets, oil cooler lines, aluminum radiator and the list goes on. I was left with an occasional intermittent crank but no start, but it would immediately fire up on the second attempt with the key. Turned out the camshaft position sensor I used was a Walker brand.... and keep in mind there were no codes in the PCM. Swapped it out for an AC Delco and the problem is solved. 2 weeks of frustration checking all connections, grounds, fuel pressure, injectors, etc.

Lol... and we won't even discuss that I used my impact gun in removing the exhaust and the vibration destroyed my O2 sensors....

 

I here yah..... I Am strictly a GM OEM user. I had the Crankshaft Positioning Sensor go on my 09. Also the Knock sensors on the outside of the block poop out. Went GM OEM no Problem after replacement. I have tried the Overseas Gack... Not worth it. Might be cheaper but when you have to do it twice you have to figure your labor time in. Might as well bite the bullet and do it right the first time.

Now I'm on the hunt to replace my Rotors. There are a bunch on the market from American made to Overseas stuff. But I have read that the GM ones are "FNC treated. Here's the Definition From Google:

Ferritic Nitrocarburizing (FNC) is a process used to reduce corrosion on brake rotors. FNC eliminates “lot rot” by drastically improving the rotors cleanability. Brake pulsation due to corrosion is eliminated when FNC is applied. FNC Brake rotors last longer because of their resistance to wear and corrosion.
I've seen them listed at $140.00 each. But I have a GM Discount form from my bud who was a GM employee. Don't know how much they will be with the discount, but I will buy the FNC GM ones..