Hi! This is my first post, though I have been reading posts for about 6 months now. There is TONS of useful information and knowledgable people here! The problem I'm having is a vibration with the a/c on. My compressor went and we replaced it about 2 months ago. About two weeks after replacing it, I noticed a vibration as soon as the tach hits 3grand. If I turn the a/c off, the vibration quits simultaneously. Anyone have any ideas on this? And one more thing... We installed the Flowmaster catback, and it still wasn't loud enough for me. So, we deleted the cat and now it's perfect (and I picked up 3-4 mpg/city!!!)... Except when I'm shifting, I get a little pop/crackle out of the exhaust. Any ideas?? Thank you in advance for your help!!

 

Take a look at the A/C mounts. Tee rear one can crack or break, freeing the compressor to move around under load....

 

Thanks... I will check it out today and let you know!