For a little time now my truck picks a day to take off from work. It had been for the month of Dec was monday.....Now its today. Once I get it cranked its good for a week. To get it to crank I put it on a charger,and yes the battery and connections to it are good. I give it hell for a couple minutes it cranks...or 1 to 2 times every hour for 3 to 8 hours then it cranks. No tools to check pressure but do smell gas...and it rumbles a bit when I turn it off to start over. It shows no codes for the longest time till now.....p0026 and p0031. The first, most I talk to scratch their heads and don't know anything about it. The other is new as of today......what gives? Its an 03 4d blazer 4.3 v6.....where are these things at? how much to fix?......and is this the reason for the no crank?......and other thoughts to help me fix it thanks..........