99' 4 runner crank but no start

Grandson leaves football practice and his 4 runner won't start. 3.4 v6 180,000 miles. When we first bought it we changed the timing belt and a few other things. Running fine since. I bring him 5 gals of fuel just in case but still no start. Son goes back 2 hours later and it starts right up. This morning no start again. I've been researching all day for things that could cause the problem. I'm old school and have done work on cars most of my life but all these sensors have me baffled. Where should I start my diagnosis?

 

fuel pump or filter...clogged fuel lines?

 

Just had my in the shop wouldn't start. tuned out that my gas gauge was broken and I was out of Gas.. long story. Either way Tech owner doing work on Toyotas for over 35 years said he has never seen a fuel pump go out on these 3rd gen 4runners. mine has 273,000. and he said even with a clogged filter it will still run. Sounds like something electrical. I take it it's cranking so not a battery or ground issue... From my understanding across the board if it is a sensor then you will get a check engine light. Any check engine light?

 

Update on my grandsons no start. It turns out he left his keys in the locker room and tried to use a hide a key that didn't have a chip. Once it started with another key at home we were able to figure it out. He wasn't aware that keys had a chip.

 

live and learn. great news!