Q: p0021 Engine Light Code and trouble accellerating to faster speeds

The underlying cause is most likely among these possibilities: 1) blocked oil passages due to sludge; 2) faulty wiring to the camshaft oil control valve; 3) a faulty camshaft oil control valve; or 4) faulty timing chain and/or camshaft phasers. Blocked oil passages and faults in the control wiring are most likely, however, in practice the way this is diagnosed is via a decision tree that is published in the factory service manual. Note, too, that loss of power although maybe partly explained by the code (P0021) can be caused by additional faults some of which will not show up as trouble codes. If you want the required diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a a Check Engine Light diagnostic and the responding certified mechanic will investigate and resolve the issue. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.