Latest in a long line of code chasing PO 452, low input pressure. AZ'* troubleshooter suggested replacing the sensor on the tank, which I had done, didn't fix the problem. I saw in related posts here, to check the lines from tank to cannister. I replaced the rubber hoses that go to the cannister (after I found the darn thing!). I was thinking about using compressed air to speed the process, but don't know if that would mess anything up. Thoughts?

You should use a decent scanner and see what the pressure reads from the sensor. You can also command to pressurize the system to test for that code. It'll cost you as much to have it done at a shop as to buying a scanner and doing it yourself. It will also come in handy in the future.

Don't use compressed air to test this, unless you're talking about 1PSI.