tpms was on this morning. I checked throughout the day for a flat but there was none. Went to the gas station to fill up and every time I uncapped a valve stem I could swear I felt a leak. this is on all 4 tires.

measured the pressures and only 1 was down though. low 20's or so. filled up the right rear and after a mile the tpms light was gone.

going to bring the tire pump to save 75 cents at the gas station.

anyone ever have valve stem problems?

 

I would check that one tire for leaks. Apply some soapy water all over the entire tire and watch for bubbles.

You can also use that soapy water on or around the valve.

Try tightening or replacing the valve core if leak is found.

 

Be aware that the process of checking the tire pressure will cause a small amount of air to leak out. Unless your technique is incredibly perfect, you will get a small hiss of air every time you put that gauge on the valve stem. If you checked the tires several times, you may actually have unwittingly bled them down a few pounds. If you have re-inflated them (presumably the tires were fairly cool at time of re-inflation) just wait a few days and see if you get the TPMS warning again.

 

Coat the stems and seal with soapy liquid and see if you can observe foam. And that can be seen even overnite sitting still.

 

+1 and if you did see some bubbles then yes it the stem causing the leak.

 

Bad valves can cause air leaks, so your tire could be perfectly fine.

I'd check for tire leaks first and if it was all at the stem...deflate, work tire halfway off if you know it's just the valve, replace valve, test, balance, remount.

 

OP said it feels like all 4 valves are leaking that is sooo unlikely.

Some nails or metal chunks are very hard to see, can look like a pebble stuck in the tread
or
change in weather, or just the slow gradual loss that happens maybe no big deal.