Hesitation & Sputtering

Just purchased a 89 Deville off of ebay for my parents. I did notice some sputtering and hesitation from the car while driving home. Here is an email that I got from someone one ebay, does that sound correct:

"hello, I see you won the black caddy.i am a caddilac mechanic and thoght you should know.he said it hesitates and idles rough.its not a sticky valve.he also said the motor mounts were bad,this can cause a bad ground that causes a short in the ignition which makes it run badly.to fix this go to wal mart and get a big battery cable with bolt holes in both ends.attach one end to the left side facing the car to the top of the left strut tower. attach the other end to the ground/alternater connection right behind the alternater on the engine block.there is a bolt there with lots of wires.put the ground cable on first then put the other wires on and tight good.if the bolt has corrosion clean with wire brush.clean the strut mount bolt too.this should solve the problem.I telling you this because nobody knows about this.GM put out a bulletin years ago but its lost.I went nuts with a fleetwood that was like that and learned about it put the cable on and no more problems."

Any thoughts?