General Motors is removing some fuel-saving features from certain truck engines. The move isn’t by choice, but rather necessity. There’s a shortage of parts used to craft the automaker’s Active Fuel Management and Dynamic Fuel Management systems.

In a memo to dealership today, GM says it is pulling AFM and DFM from certain 5.3-liter V-8 truck engines, reports GM-Trucks. Both features rely heavily on semiconductors, which all automakers are running short on due a global shortage. Running out of options, GM is just scrapping the features to keep its truck plants in supply of engines. The engines are used on several variants of the Chevrolet Silverado and GMC Sierra.

GM will start building 5.3-liter’s without AFM today, while production of the 5.3-liter without DFM will commence on March 29th. Pickups built after these dates will lack these fuel-saving features, which GM will denote on the window sticker. Trucks not equipped with AFM or DFM will also see a modest $50 credit on the MSRP. Impacted trucks will also see modified EPA fuel economy ratings, though GM has not disclosed them.

AFM and DFM are similar in functionality. AFM allows the engine to run on half of its cylinders during light loads to conserve fuel. DFM is slightly more advanced in the sense it can shut off the fuel and spark to any number of cylinders based on load, meaning the engine can run on any number of cylinders. AFM has been widely deployed on GM trucks for a number of years, while DFM is been used more recently.

GM has had to idle several assembly plants due to the ongoing semiconductor shortage. The automaker has purposely idled plants that produce less popular models to maintain steady production of profit-inducing trucks and SUVs. Given the alternative would be to stop producing pickups equipped with the popular 5.3-liter V-8, this move comes as little surprise.

At this time GM does not have a date in which these engines will regain AFM and DFM functionality.