Truck struggles to start

2018 5.7
I work from home so I don't drive everyday. If my truck has sat for a few days, when I go to start it, it struggles to start. It cranks fine and the battery is about a year old so I don't think it's that.
I'll bump the key and let go and it tries to crank for a few seconds. If it doesn't start, it will stop trying to start.
If it does start, it just sputters to life and slowly gets up to speed.
After I drive it, it starts immediately. Even starts fine after sitting overnight. Only does this after a few days. That's why I don't think it's the battery or starter.
No rough idle, no loss of power, no lights on on the dash. Runs normal after starting, just difficult to start after a few days.
As y'all are aware, when you first start these 5.7s they sound like a jet taking off, then after about 10-15 seconds you'll hear a "pfffft" and they idle down a tad. Mine doesn't do that anymore.
I've noticed that it wouldn't do that for a while and it gradually got worse until here we are now, with what I described above.
What say you guys?
Thanks

 

You dont mention miles on the truck. Are service items like spark plugs, air filters, etc up to date and replaced?

Batteries dont do well with sitting. Id have yours load tested. Being a year old means little, Ive had brand new batteries go bad in weeks. And the battery is has enough CCA/power for the truck? Its shocking how many people install batteries that dont meet a vehicles CCA requirements....trying to save some $ and go with a smaller battery.

If your truck sits a lot, it could also be fuel related. Ethanol gas does go bad and starts absorbing moisture from the air in just a couple weeks.

Check battery first- for load test and full charge.
Check air filter
Check plugs/coils
Check MAF wiring, may need a cleaning depending on miles
Try a fuel system cleaner, treat fuel with and ethanol treatment.

Id start there, could be other possibilities but you need to rule out these before moving on.

Lastly, If it as sat a while, turn on the ignition for 30 seconds or so before turning further to start....That will give the fuel pump some time to get power/prime before you are trying to actually start.

 

I would guess your fuel density level needs reset.

 

Good point on fuel....is the truck the regular 5.7 or the 5.7 FFV? FFV can have issues and may need the alcohol level reset. There are threads about that here with details and procedure.

 

FFV, 92K miles, original plugs, air filter good.
It rarely sits more than 3-4 days without being started. Not like it sits for weeks.

I thought you were messing with me but after reading this...
Reset Flex Fuel Alcohol/Ethanol Percentage Level with Bidirectional Scan Tool | Toyota Tundra Forum
This may be the problem.

I think I'll put some Startron in it and use up this gas. Maybe then run some ethanol free in it and start cranking it everyday.
If that doesn't change anything, I guess I'll be buying a scan tool.

 

I bought the bi-directional scan tool to reset mine.

It was sluggish on initial startups in the mornings, reset it and all was well.

 

You stated your battery is fairly new but sometimes you need a higher power battery that helps. I swapped mine out and made a huge difference