Hi, just recently my 97 Civic d16y8 has been getting 5mpg less than it used to and after about 30 minutes of freeway driving I pretty much lose all my power and have to shove the pedal to the floor just to try and keep up with traffic. Everything on the car is stock and it started doing this a little less than a month ago, no check engine lights are on either. Any thoughts on what might be causing this are appreciated, thanks.

 

Does the CEL work? If so, do a full ignition system tune up.

 

Yeah the CEL works, do you think it could be the Catalytic converter?

 

Could be bad o2. Personally doubt bad cat but maybe.

Timing could be off.

Check spark plugs for how lean you're running.

Might be fueling issue, but I'd say less likely. More likely a sensor issue if it develops after time.