96 GP shakes when AC is on

[Brodizzle83]

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.

 

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[Galaxie500XL]

Generally, the ECM bumps up the idle when the compressor kicks on..what is your idle speed?

[Imp558]

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.

[Schurkey]

What is the idle speed?  What is the high-side pressure?

[oldmangrimes]

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

[Brodizzle83]

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.

 

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[Brodizzle83]

First pic is completely stopped in "drive" with my foot on the brake. Second pic is completely stopped in "park".

[Imp558]

Does it hold steady or does the tach move around at idle?

[Brodizzle83]

Does it hold steady or does the tach move around at idle?

Holds steady.

 

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[jman093]

Worn motor mount(s).