what will cause for my 1999 Honda civic lx to start using twice much gas
air filter. maybe needs a tune up
Make sure that the transmission is shifting properly and it's going into overdrive with torque converter clutch lock up. If not, it'll kill your gas mileage. At expressway speeds (60 to 70 MPH) your engine should be running at around 1200 to 1500 RPMs. If not, it's a transmission, as described above, problem. HTH. -Jim
Search Honda Civic Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Honda Civic Experts