I just found out that the hose was not connected for a while. I did not notice any difference after connecting it back. What will be the long term effect if that was not connected. Picture reference attached. Thanks

 

Doubt any long term issues. May have had a SAI code?

Found same, pushed hose on/in nipple/boot and higher than normal idle RPM was miraculously closer to the manual specs. If worn or oil soaked a small cable tie(s) should help prevent it from coming loose in the near future.
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^^

None really. It's the hose providing vacuum to the SAI valve(s). Normally throws 1412 and 1415 IIRC, if it's off.

The rubber connector gets loose with age and can fall off in my experience. Might be worth going through the he vacuum system with new hose and rubber connectors. Doesn't cost much, if you have the time

This is your new truck? The check engine light is working, right?