Driving to fast
While an incorrect fuel/air ratio can cause a misfire, it's not likely to cause only one cylinder to misfire unless you have tuned port injection. The more likely cause is the ignition system... Distributor cap, rotor, plug wires, or spark plugs.
What causes a car to jerk while driving can be based on many factors. A car can sputter due to engine compression issues, bad transmission, engine misfire, bad spark plugs or even low fuel.
Could be a number of reasons...I would begin by replacing your plugs and wires if it does not misfire at idle, then that usually means you have a cracked plug, or faulty wire.
If your 1997 GMC 5.7L Vortec has a misfire at an idle but not while under throttle, the problem is likely the timing. This can be adjusted.
The timing is set higher than recommended. It needs to be retarded.
most 2000 model year focus have a fuel delivery module recall.
It started a while ago in around January 2009
check plugs &wires
It is timed incorrectly or plug wires are installed incorrectly.
Probably have a misfire or lean fuel mix NELSON
First remember this rheostat is connected in series with the armature to increase the total resistance to limit the starting current, thus achieving max starting torque from the motor
The Famous Five series was written first, starting in 1942. The Secret Seven series was written later, starting in 1949. Both series are popular children's mystery books by Enid Blyton.