I have a 2006 Chevy Silverado 1500. It's been skipping for several weeks now but not really throwing a code. I've changed the fuel pump and spark plugs but still skipped. Then I came out one day and it wouldn't start and the battery died while turning over trying to crank. I hooked my battery to another vehicle and jumped it off. The skipping seemed to stop while the jumper cables were on but as soon as they were taken off it started skipping once given gas in park so I got a new battery and alternator but still no luck. Now it'll stop skipping for several hours or even days then all of a sudden start back. I've waited until it was dark and looked for sparks to suggest a grounded wire but with no luck.
Now after the holidays and being off work any time my truck has sat over 12 hours it acts like it doesn't want to crank. It has good fuel pressure, also most of the skipping is when the truck is about to shift into second or third gear. Like I said also skips/misses in park.
I'm out of ideas. What does it sound like the issue most likely is?