My rear left tire is losing pressure slowly. I just got my car (2.5TL) about 3 weeks ago from a used car lot, with only 1 month warranty on lubricated parts. I can guarantee it was like that before I bought it. Yeah, I checked the tire pressure a couple of days after i bought the car and it was the same tire. Thought nothing of it and filled it back up. In about 2 weeks, it went down to 25PSI from around 30 and only on that tire.

How do I fix the problem? Oh yeah, i'm a total noob to cars.

 

Go to any garage or Tire delaer and get them to check the tire. Its not expensive to get it checked and fixed.

 

thanks. Les Shwab told me about 12 bucks...other places wanted 30?

 

Since its only a slow leak, I would go buy a can of fix a flat for $4, put it in the tire when it reaches the low 25psi and the problem will most likely just go away.

 

Go to a reputable tire shop and have them look for leaks. It could be a leak in the tread, sidewall, that it wasn't sealed around your rims properly, the rims could be very rusted and not causing a proper seal, etc. They all need to be treated differently. Check the tread yourself to see if you can find anything stuck in the rubber (nail, screw, etc.) The tire shop will spray liquid on the tire and rim to see if anything bubbles (shows air leaking out). If it's a leak in the tread, always remember that an internal patch is much better than a plug. However, a patch will require that they take the tire off the rim and patch it, remount it, balance it, and then put it back on the car. They don't need to take the tire off the rim for plugs. If the rims are very rusty, then they will need to sand that down.
Leaks aren't very expensive to fix at all.