Brodizzle83 Posted July 9, 2018 Report Share Posted July 9, 2018 Does anyone else's Grand Prix or 1gen W have this issue? Feels like I have subwoofers in my car when at a stop light. Sent from my SM-G955U using Tapatalk Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted July 9, 2018 Report Share Posted July 9, 2018 Generally, the ECM bumps up the idle when the compressor kicks on..what is your idle speed? Imp558 1 Quote Link to comment Share on other sites More sharing options...
Imp558 Posted July 9, 2018 Report Share Posted July 9, 2018 It probably is idle quality but if it's thumping like Magic Mike it may be time to get down and inspect the engine mounts. Quote Link to comment Share on other sites More sharing options...
Schurkey Posted July 9, 2018 Report Share Posted July 9, 2018 What is the idle speed? What is the high-side pressure? Quote Link to comment Share on other sites More sharing options...
oldmangrimes Posted July 9, 2018 Report Share Posted July 9, 2018 (edited) Last weekend I recharged the A/C in my 1995 after a couple years of not using the A/C. I was happy that it still works, but it does increase the idle speed by at least 200 rpm. Like yours, it now makes a bad vibration sound at idle, and the vibration also causes an annoying buzz in my dash somewhere. Everything smooths out above 1500rpm once I start driving, it's just noisy at idle. It's bad enough that my 9-year-old son asked me yesterday "dad what's that weird sound?" at the first red light. My motor mounts are probably pretty bad after 231k miles, I'm getting a little "clunk" when shifting out of Park. Edited July 9, 2018 by oldmangrimes Quote Link to comment Share on other sites More sharing options...
Brodizzle83 Posted July 10, 2018 Author Report Share Posted July 10, 2018 I would have to see what my idle is at. It shakes a little when the AC is off too, but not as bad. I'm now guessing the engine mounts are toast. Sent from my SM-G955U using Tapatalk Quote Link to comment Share on other sites More sharing options...
Brodizzle83 Posted July 10, 2018 Author Report Share Posted July 10, 2018 First pic is completely stopped in "drive" with my foot on the brake. Second pic is completely stopped in "park". Quote Link to comment Share on other sites More sharing options...
Imp558 Posted July 10, 2018 Report Share Posted July 10, 2018 Does it hold steady or does the tach move around at idle? Quote Link to comment Share on other sites More sharing options...
Brodizzle83 Posted July 11, 2018 Author Report Share Posted July 11, 2018 Does it hold steady or does the tach move around at idle?Holds steady. Sent from my SM-G955U using Tapatalk Quote Link to comment Share on other sites More sharing options...
jman093 Posted July 11, 2018 Report Share Posted July 11, 2018 Worn motor mount(s). Quote Link to comment Share on other sites More sharing options...
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