I have 2000 Buick Regal GS with 130,000 on the clock. Overall she has served me well over the last 8 years. Recently, she has developed an issue I can't seem to put my finger on. I'm hoping to get some starting points and go from there. Between 35mph and 45mph only under acceleration I am getting a very strong shimmy or shake. It moves the entire car and doesn't seem to come from one certain spot. Before 35 and after 45 it is smooth... First I thought it might be an alignment issue or tire issue, but it only happens under acceleration. But, if I hammer the gas or use strong acceleration it is not there. It only happens under normal driving. The car still drives well and has plenty of power. Everything is in good working order except I need a battery really bad. If the battery sits more than a day or so, it dies. But, that should have no bearing on this issue. I did a full tuneup and all fluid flush at 70,000 and I know she's due for some maintenance intervals, but again, I don't believe it's linked to this issue. Money is tight right now, so I'm trying to do as much as possible by myself. Thoughts? Where do I start?