Vibration when accelerating hard at highway speeds
Recently purchased a 2004 S4 manual with 53K miles, on the way back from dealer, noticed a vibration when accelerating hard at highway speeds 60mph to 80mph roughly. Now this is the first time owning a car with a V8, so not sure if it is just a combination of the age of the vehicle and/or the power from the engine. It is not a violent vibration, but it can be felt through the steering wheel and I noticed the mirror slightly vibrating when changign lanes during acceleration. One acceleration stops and just cruising, all vibration goes away. Car feels great and extremely responsive otherwise. Just inexperienced with this type of engine/car. I do own a 2008 A6 3.2 and when pushed, there is no vibration at all, but there is also a difference of 100hp and 50tq. Again, this was under hard acceleration. Runs smooth when driven normally.
It doesnt sound like a V8 issue. It sounds more like a possible bad cv joint, axle, or maybe even something in the transmission.
I have the same problem with my 98 2.8. It was my tires, and my wheel bearing in rear tires, and a drive shaft in the front. Happens when cars sit for a while. It wouldnt be the tranny. Wouldnt be the engine niether. My advice it to take it back to the dealer under your 30 day lemon law warrenty, and tell him to check your driveshafts, tires, and wheel bearings. Look in your book to find out the correct way to rotate the tires cuz i can put my money on it that he didnt do it at all. Also, make sure u watch him do repairs as s4's can get pricey when people mess them up. Great car though. Dont get rid of it
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