My car has been running really rough, it starts just fine but when its at idle the rpms jump up and down, and stalls. When driving down the road it tends to jerk a little too. Once it warms up to operating temp it smooths out a little but still runs and sounds bad. I went to the parts store and had it scanned and got two codes a p0125 which means closed loop fuel control and insufficient cooling temp. the other code is p0171 which is a system lean bank. I changed the cooling temp sensor to see if that was the problem and it was not. Could this be either a bad MAF or a vacuum leak?