Chug, chug
 

My FC has been running a little odd lately. In any gear around 2500 RPM if my foot isn't on the gas pedal, it chugs slightly as if its going to die. It doesn't die, it just makes you bounce forward and backward in teh seat. The lower the RPM, teh more severe the rocking. I took it to a shop and the mechanic told me it was problem with the clutch tow cable, though when he raised it up and took a look the scam artist was wrong. I'm wondering if anyone else had this problem or might know what is wrong?