I have one tire that seems to be leaking air. I check the pressure every other day and its at 20 even though I pumped air the day before. All my other tires stay around 32. Does this mean this tire is dead? Do I really need a new one?

 

Other things to look for are:

screws / nails... in the tire (I have had 3)

a bad valve stem (I have had 1)

buildup / rust on the rim (I had this once).

To fix the buildup on the rim they will grind the seat on the trim where the tire meets up.

 

But it's not as bad. If I fill it to 34, about a week later it'll be only 31 or so like the rear tires. All other 3 tires will be exactly the same. I do notice slight cracking on my sidewalls, but I don't think that's it. It may be a valve stem in my case. I'd take your car to a tire shop and see what they find because it sounds like your leak needs to be stopped.

 

here in southern california most shops charge $10-15 to get a tire checked for leaks and to fix a possible problem.

however, if you're a costco member, its free at costco tire center.