If no one is letting the air out of the tire, YOU HAVE A LEAK - no matter what the tire center says.

Given the randomness of when you have to add air, would suspect that there's something that's punctured the tire and depending how it positioned on the ground when it's parked it allows it to leak. *Have seen and personally experienced this myself.

It may take dismounting the tire and doing a physical inspection of the inside to determine the cause of the leak.
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Or your valve stem is loose. try tightening it up.

 

I hated when I used to get those kind of leaks, pita to find them, we used to over inflate them and stick em in a barrel of water to find them.

Sometimes we would over inflate them and leave them on the vehicle spraying with soapy water as someone else slowly moved the vehicle until we saw bubbles.

There were a few times a bad weld on the wheel itself leaking.

 

the only good thing about a really slow leak is that all you have to do is keep an eye on it and air it up every couple of weeks with a few lbs ... other than that, they are a real pain in the butt.

 

Worked in a gas station when max inflation pressure on car tires was 32psi. We would air them to 50 to find the slow leak. Many times it was around the rim where the bead seats to the rim. Put the tire valve side up flat on the ground and pour a few oz of soapy water along the bead. Repeat for other side.

Practically sure fire method is to fill a large tub with water and submerge the whole thing.

 

You can get a tpms that gives you the information for $119 plus shipping.



So I guess the guys beating up the OP for wanting the information must check the oil and coolant once a month and have no need for gauges in the dash. Stupid, right? Of course it is. You want to know if the oil or coolant has a problem, right ... ? Or maybe you don't. Why wouldn't you want to know if you've picked up a nail during a trip and have a leak in a tire (and which tire) before the stupid tpms light goes on? Just because you've never had it and maybe you don't want it, does that mean you should show the guy a picture of a pencil gauge or tell him to check the air like he's an idiot? I suppose you could complain about having an oil pressure gauge and show pictures of a dipstick.

I use a TireGard tpms on both my motorcycles. It alerts on hi/lo pressure and temp limits you set yourself. On those occasions when I've picked up a nail (both times on the rear) it was good to know what was going on. In one case it let me know (in AK going home to VA on a 1-day old tire) that the leak was slow enough that I could pop a little air in every morning and the pressure increase from the temp would overcome the leak until the end of the day. You could actually see it on the gauge. I made it home without screwing with a repair on the road.

 

Why I installed the Kenwood in my sig. It allows me to see the tire pressure in 'real time'.
BTW your F150 oil pressure 'gauge' is run by a switch. Not a gauge by my standards.

 

Got TPMS fault on my F150, the guys in the Ford garage said they need to replace al 4 sensors as they can't read them at all. So this is how I got installed 4 brand new TPMS-12- 9L3z-1A189-A.
Now the thing is that they were not able to "train" them. They tried all the tools they got, they did a system reset, the tried with another receiver module... Nothing. Anyone experienced this?
Tx.

 

Changed the tyres with some nice black 275/60/20, the truck looks cool indeed, but I got the faulty TPMS warning message and light on, of course, as these tyres were equipped with some GMC 433Hz pressure sensors. Went to Ford garrage and they changed all four sensors, got some brand new TPMS 12 9L3Z-1A189-A installed. Then the training struggle begun. Sensor are responding to their training small devices but their readings are not processed by the TPMS unit. The unit is functional, they tried it on another truck and they also tried another unit on my truck but even the other unit was not processing the sensors readings. They came with the laptop, they did a lot of tests n resets but nothing.
Any ideas? Any experience with this?
Tx.

 

Did you try training using the truck itself? For my 2011 there is a training procedure in the owners manual.