5.3L tahoe, cranks, hesitant to start

[NOS327]

Hi, I've got a 2001 tahoe with a 5.3L. I've recently put a new fuel pump and filter on it, been running great. Also put new plugs and wires on it, been running better than ever before. A week ago I jumped in it and it cranked, but wouldn't start. Then crank crank crank crank, and it finally fired. Odd. Took battery to get tested, was at 54%, said it had 2 dead cells. Replaced battery, been great for a week, then this morning, crank crank crank crank craaank, finally hits. Don't know what's up. Can hear fuel pump running. Voltage well above 14V on gauge once started (had replaced alternator probably 2 years ago). I'm not sure what's going on. Someone suggested security/anti-theft deal. The security light is not flashing while cranking.

Any suggestions?

This particular vehicle has had a few electrical gremlins, the a/c relay crapped a year ago out of the blue. stuck the horn relay in that plug until buying a new one. put new in a/c spot, put old horn one back in its place, horn sounds sick now. Recently lost the lights in the face of the radio. Goofy things. So I suspect that it's electrical connection related. Maybe in crank or cam position sensors, or MAF??? I'm stumped..

Anyone have similar experiences in truck or other applications?

thanks,
TJ

[silverz28camaro]

Is the throttle body clean? make sure, I would get a spark checker and with someone else cranking see if it has spark, if so then move to the fuel side, get a fuel pressure checker and monitor psi with key on and cranking I would think it would be near 40psi at least.

thats a start. any check engine codes? Did you get new spark plugs?

[NOS327]

yep, new plugs.

will get someone to help check spark for starters, then get after fuel.