Hello all,
First off thank you for your help when diagnosing my issue with the COPs, changed those and seemed to fix the issue of sputtering/skipping. Soon after I changed those I starting hearing a random sound in the engine bay that sounds like beeping or maybe a slight whistle. It goes away once the truck is warm but it very annoying and cant seem to figure out what it is. I have 120k miles, COPs changed 2 weeks ago and spark plugs changed about 35k miles ago. Everything else seems to be ok and is driving fine just want to fix the issue. also no codes came up when I ran it at Orielly and engine light is not on. Thanks for the help and have a good day.

p.s. I tried to make a video but was very hard to hear the noise

 

Vacuum leak?

 

Vacuum leak could be the issue but strange how it happened right after I changed the COP and makes a beeping noise only at start up. Could be that I knocked something off and makes it only while the hoses are "cold". Is it better to use propane or starting fluid to find the leak? Thanks for your help