My son drives my 2003 A4 3.0. This week he called to tell me it "shakes" while accelerating roughly between 40-60 mph.

My first thought was ignition coil. I've experienced that "shake" and it's pretty rough.

So last night I drove it... It's not an ignition coil based on my prior experience, nor is it throwing any codes or tripping any idiot lights... so i'm kind of also ruling out intake leaks.

It feels like a side-to-side shake as I accelerate, not a sputtering "I don't want to go" kinda shake. It only does it during acceleration. If I release the gas while it's shaking, it stops immediately.

He says its been happening for about a month... but i'm not sure of that.

Thoughts or suggestions? The car has 158k miles on the clock..

//Brew

 

I had a Very similar issue on my 03 Cabriolet 3.0. My first thoughts were clutch or/and Dual Mass flywheel, However turned out to be the alloys were more egg shaped than round where the previous owner hadn't been so kind to her over the pot holes.

 

I agree with Town. Just had my car in for tire repair and alignment. And was told that three of my rims were bent and that was probably causing my side to side shake above 80 mph. Other than that the car is very tight, gets aligned twice a year and I just changed the lower control arms. But still get the high speed shake. I may invest in new wheels this year if I can confirm the bent wheel theory.

 

have u checked your cv boots? a leaking axle might cause this.

 

If you have been told your Alloys are buckled then you need to start with that, when I had mine I went through exactly the same steps as you, I replaced all the tires, had the alignment done, not seemed to do the trick until I replaced all the alloys.
If you are from the UK LKPerformanceparts do some really nice Audi replica wheels for a fraction of the price you would pay.
lkperformanceparts on eBay

 

If his wheels are bent and you replace them with cheap wheels you well have this problem again