[racer_d]

One question I would ask was did you measure them all at the same time under the same conditions?

If so, then yes, I could see your concern, especially with a 7psi difference.

Like most things, gauges wear out over time. I have a Longacre brand unit I bought from a race shop (Pegasus?) a coulde of years ago. I have no idea how "precise" it is after several years, but even if its within 2-3lbs it can still be good.

For regular street driving, I don't think I would worry too much. Can you "feel" the difference when driving? Do you notice unusual tire wear?

Now, if you are competing/racing, than I would prefer to start out with an accurate guage. On the other hand, its all relative. if "36" feels low, put a few more in. If "36" feels high, then let out a bit.