00 vw cabrio dtc p0121. What is proper diagnostic procedure to eliminate all possible culprits?

Question

Engine starts cold, at 40c engine temp. Engine begins rough run, then dies, will not restart. Engine cranks, won't start. Charging system puts out 14.6 to 14.8, no apparent current draw with car at rest. Battery won't hold charge. Possibly the cause?

Answer 1

P0121 Throttle / Pedal position sensor / switch A circuit range / performance

The code P0121 does not fit the description that the vehicle has , if the throttle position sensor was faulty it would get set at a specific position with a increase in idle. and be in a limp mode. The fuel pressure should be check the specification are 2.5 bar. The battery should also be replaced if it can not hold a charge.