loud noise from air filter

I have a horn type sound coming from air filter on 01 Lincoln tc.
What could this be?

You'll have to pull it apart and have a look. Could be a sensor module, a rats nest, bee hive.. etc.

Steven, I have taken the filter out and checked all the line, everything seems
ok but still have noise at entermitte times, what sensor could cause this

The air compressor for the air ride suspension is located under a plastic panel under the air filter box, it could be the cause especially if it is intermittent.

Sounds like you need a hooter hose.

I have a horn type sound coming from air filter on 01 Lincoln tc.
What could this be?