Car has starting surging a lot recently. It did it occasionally before, but after I put my long tubes in, it doing it A LOT. I'll be sitting still, then all of a sudden the rpms start to go down then jump up and it pulls on the brakes. It'll jump up to about 1300 rpm then will die back down. What could cause this?

 

first thing to check is vacuum leaks, Then i would check plugs & wires.