Fluttering sound when stepping on the gas

When I start the car in the morning & step on the gas there is a fluttering noise which happens each time I accelerate until it warms up. I bought the car with 17,000 miles on it and I didn’t notice it happening then, but it was warm weather then. Any suggestions?

It could just be tires but your question may be one of the tougher ones. I wouldn’t know where to start without driving it around. Hope somebody has a bit of experience with this one.

Maybe an exhaust manifold leak?