[Tarquin]

After searching this awesome forum, I could not find anything matching this exact condition so I am reaching out for help!!

2010 Titan 4x4 with 156k miles, California emmisions, new battery, 12mpg (🤮)
Symptoms :
intermittent non start
hot engine, stopped at a customer's home, wouldn't start when I came out
engine cranks perfectly, normally starts immediately.
when it won't start you can hear the fuel pump pressuring up when the ignition is turned on, then stops when pressurized as normal.

the first time it happened I stopped at the end of a long bumpy dirt track so figured fuel pump switch. thumped the fuel tank a few times and it started immediately.
the day after stopped at a customer's house off a smooth surfaced road, came out, wouldn't start, thumped fuel tank several times and wouldn't start. Repeated this a few times no start. This problem began after getting the new battery, so disconnected and re connected to reset the computers. Engine started first time.
Drove to the job site on an unmade bumpy road, stopped to pick up one of the guys, you got it no start. Thumped the gas tank no start, disconnected/reconnected the battery no start
Called AAA to take it back to the shop, arrived an hour later, truck started first time 🤯
Drove it back to the shop and it has started each time since.

Any and all help is appreciated

 

[busemans]

Is the starter just going out? Next time tap the starter with the end of a hammer or a screw driver and see if it starts?

Or the starter relay?

 

[dubyam]

Pretty hard to tap the starter on the Titans. It's under the intake manifold. I'd like to choke the engineer who dreamed that up.

 

[Tarquin]

it is amazing, it is not until someone else reads what you have written, you realize how confusing it is, despite it taking an hour to write and re-write to make sure it is perfect! Thanks guys.
It always cranks perfectly, so it is not starter or battery, it just doesn't fire up every now and then.
This may take the hounds off the scent or let them find the guy, but another factoid is that I haven't used the truck today (it is His day) and it has started from cold every time I tried it I just can't risk getting to a customer's house and have it not start. Sitting on the end of a driveway waiting an hour for AAA is really uncomfortable, especially as the first time he couldn't get his car out.

 

[Tarquin]

again, This may take the hounds off the scent or let them find the guy, but just for reference it 'feels' like an engine immobilzer situation when it happens

 

[busemans]

i have no ideas. is the battery good in the fob?