East Coast Cars

• There have been reports of vehicles coming from the East Coast which have had their CNG systems disconnected by the cities surplussing the vehicles - despite the seller claiming otherwise.

Bi-Fuel Fords

• Bi-fuel Fords have had issues with the Compuvalve (the part that controls the amount of CNG going to the motor). The problem generally manifests itself by having to crank the car for a while in CNG mode to start or not being able to start at all in CNG mode. The part is expensive (like $1500) but may be covered by Ford's 8 year / 80,000 mile CNG system warranty. In speaking with a Ford mechanic, he told me that this can be a problem on vehicles that were not used in CNG mode very often.

Honda Civic

• The continuously variable automatic transmission (CVT), specifically on the 2001 Honda Civic, has had a number of problems.

In General

• Sticky valves, broken regulators, etc. occur from time to time, especially on bi-fuel vehicles that were not used in CNG mode very often. I would recommend the following for any CNG vehicle that you contemplate purchasing:
  • See it in person
  • Test it thoroughly - make sure it runs (and runs well) on CNG
  • If it sounds too good to be true, there's a chance it is too good to be true