You're not alone....
Jon... . there have been other posts about this fogging, and I'm just now experiencing it on my Z series fuel pressure guage.
I talked with Autometer yesterday. If you return the guage they will replace the lense with a non-fogging one. They apparently got some bad glass lenses in production last summer. I bought my guage in August. They are warrantied for 12 mos. They won't send you the lense to do it yourself.
Sorry, I'm not where I can get phone number, address, etc. Some TDR have gone through the vendor they bought the guage from.