New York CNN Business  — 

A computer chip shortage has long been dogging the auto industry — and now, it will mean added costs at the gas pump for buyers of some General Motors pickup trucks.

GM said Monday it will build some versions of the Chevrolet Silverado and the GMC Sierra without a fuel management module that improves mileage by about 1 mile per gallon.

Unfortunately for buyers, even once the chips are available, GM will not be able to retrofit the engines with the missing fuel management module. So the decrease in mileage, to about 16 miles per gallon from 17, will be permanent.

Buyers will get a small consolation prize a $50 credit off of the list price of the vehicle. The mileage sticker in the window will also be changed to reflect a lower mileage, according to GM spokeswoman Michelle Malcho.

The affected versions of the trucks are those that have a 5.3-liter EcoTec3 V8 engine and either a 6- or 8-speed automatic transmission.

The entire auto industry has been affected by the shortage of computer chips, with temporary plant shutdowns becoming common as a result.

Automakers cut back orders for computer chips early last year when the pandemic slammed the brakes on auto sales and production — but then, car sales bounced back sooner than expected Meanwhile, the consumer tech industry had been busy snapping up the excess supply of chips thanks to increased demand for devices in the work-from-home era.

It’s all left automakers struggling with a chip shortage, and it will have a significant effect: GM has said that it expects 2021 profit will be reduced by $1.5 billion to $2 billion because of the chip shortage. The company It has temporarily shut three plants — the Fairfax plant in Kansas City, Kansas, CAMI in Ingersoll, Ontario, and San Luis Potosi in Mexico — in early February and they remain closed.

GM has also built some vehicles without missing computer chips, planning to add them once available after the rest of production is complete.

But it has been trying to maintain production of its relatively hot-selling full-size pickups like the Silverado and the Sierra, as well as full-size SUVs. These versions of the pickups are considered a “light duty” version of the trucks, with a smaller engine than the “heavy duty” models.