just had a tire pressure sensor go bad and the lexus dealer replaced it for no charge (actually its the 3rd one we had to have replaced). Now I notice that the tire has a very slow leak along the lines of losing 5 psi over a couple week period.

Yes, the easiest thing to do is to run it back to the lexus shop and wait, but i wonder if that
ring nut that you thread down the valve stem is ever so slightly lose?

Just wondered if this is a good 1st step is to try to carefully tighten that nut or will that
damage something?

i am just really confident it isn't an actual tire puncture problem.

 

You may consider a little 50/50 dish soap and water. Dab some in the valve stem area and watch for bubbles.. I had a bad valve in my stem, easy to replace with the stem tool and a new valve from an auto shop. Careful you don't scratch the wheel if you try to tighten the stem mounting nut. Lay down some tape to protect the wheel.

 

Make sure you or your mechanic is very careful in careful in tightening the valve stem. The previous owner must have tightened one of mine too much or did it at an odd angle, and I had to replace an entire sensor just because it was a little crooked and they couldn't fix just the valve stem. Lexus wouldn't cover it since you could see that it was damaged.

 

if its the same tiresensor that has been replaced its under warr still