Unknown engine tick

[94 Daily]

94 cobra has developed 2 engine ticks. First one was at the back of the intake. Replaced the PCV valve and persisted. Replaced the grommet and solved it. Second tick seems to be loudest when I put my ear to the intake manifold. Sometimes it's louder than others and sometimes I can hardly hear it. I feel it's another vacuum leak. Any guesses?

 

[General karthief]

Checked header gaskets?
Do you still have the crossover pipe in the back of the heads?

 

[nickyb]

Its time you do the smoke test, find all and any vacuum leaks, stop the leaks and take it from there.
I'm old school, I don't have a smoke machine but I use a can of carb cleaner,starter fluid,or throttle body cleaner.
Find em fix em.

 

[91AOD5.0LX]

Just throwing this out here…
Great DIY smoke machine:


View: https://www.youtube.com/watch?v=VvcFGzAyaXE