99 Yukon problems

I have a 1999 Yukon Denali with about 140K on it. It is acting like it has a dead battery, but the battery is fine. So far I have replaced the battery, cables and the starter and it is still acting up. When I turn the key to ON everything is normal. When I try to start it the motor will turn over a few times then the power either faids down to almost nothing or it completely cuts out. It does come right back after that and continues to crank a few times then back to nothing. It doesn't even sound like it wants to start. It turns over freely but it never has even a slight thought of kicking over. Any help would be great before I decide to just torch the truck, thanks.

start with cleaning the battery cables were they screw up to the battery , clean and check for rust on all ground, check and clean them every 2-3 months they get real dirty on these trucks same happend to me

start with cleaning the battery cables were they screw up to the battery , clean and check for rust on all ground, check and clean them every 2-3 months they get real dirty on these trucks same happend to me


Battery and cables are new, I replaced them hoping it would solve this problem.

OK I just checked and I have spark but I can't hear the fuel pump. Is there a safty that could shut it off or is my pump just dead?

Get 12v directly to the fuel pump. should be a jumper/feed near the relay box under the hood, if still no pump it is bad, no safety shut off here.