Originally Posted by americanretrodave

I bought a new Cuda in '71, at 12,200 miles it had the same thing. it was so bad, I didn't trust it when I pulled out in traffic. I put on a new carb, no help. I finally figured out it must have had a factory vacuum leak which burnt a valve. So i had a valve job at 12,400 miles with no help from the manufacturer. Fixed the problem.

I'm not saying it's a bad valve, but I'd put a dollar bill against the tail pipe and see if it was sucked back instead of a flutter. If it does, then a compression check might be in order.

Dave