Hi I bought a Mark 8 not long ago.It's in great shape I've had to sink a little money in it but it runs good and I plan to put more in to it.The problem I'm having is that when I first start it up I have to let it warm up a little before I take off.More recently when I accelerate to about 30 or 40 mph it starts to jerk or even bog down if I let off the gas a little or even pump it it fixes itself.Plus I've had a little back fire out of my right muffler.What could be the problem?
