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Grand Marquis Shuttering

Hey there.

I own a 1991 Mercury Grand Marquis. 71k original miles. Runs and rides great, but it has developed a shutter. Heres when it happens. I slow down to take a turn or something and as I re-apply the gas after the turn, the car shutters rather violently. The car then upshifts and the shutter is gone. Seems to me like the transmission is getting stuck in a high gear and lugs the engine when I re-apply the gas. The take good care of the car. The transmission fluid is not low at all and has a good pink/red color. Any idea what it could be and if its worth fixing?

On a related question, lets say the repair costs more than 500 to fix, more than the value of the car. Do you think it is worth keeping a 1991 grand marquis with low miles that can arguably run for 50k more miles with general maintenance or should I just sell it and get a newer car with more miles?

Thanks for the help, folks. I appreciate it.


From what you describe, it sounds like the torque converter clutch is failing to disengage. This could because of a sticking torque converter clutch solenoid. It sounds like you don’t want to put too much money into this car. So, you might try adding a half a can of SeaFoam Trans-Tune to the transmission fluid. The stoddard solvent in the SeaFoam might be enough to desolve the gum and varnish that may be causing the solenoid to stick.


Ah, alright, the torque converter clutch. I’ll give the additive a try and see what happens. I can’t really go wrong. It may be a cheap temporary fix. Thanks for the reply.