Using a modified 3.6-liter V6 with hardened valves and valve seats, the Bi-Fuel Impala has separate tanks for gasoline and CNG that it can switch between on the fly. When running on the cheaper natural gas, the sedan was estimated to get 19 miles per gallon in the city and offer 150 miles of range, and the total driving distance was predicted at around 500 miles. The base price was set at $38,210, after the $825 destination charge. The only other major tradeoff was a smaller trunk to accommodate the extra fuel.
However, the first shipments of the bi-fuel models now aren't expected until mid-July – about a year later than the scheduled launch. A memo to dealers obtained by Automotive News said the sedan "has been delayed by a second quality hold" to look at the CNG system.
The exact details surrounding this problem haven't been released. "We have identified a solution to the delay and are working hard to implement it within the next few months," General Motors spokesperson Chad Lyons said to Automotive News. Around 200 Bi-Fuel Impalas have been made, but none are yet in the hands of customers. Dealers should be able to order 2016 model year examples starting in the third quarter of this year.