Poor Gas 99 Max

filipinowise · Jan 1st, 2008, 11:34 AM

My car use to burn gas great but now it the worst ever. I have changed my spark plugs, Cleaned out my fuel system with sea foam (through vacuum line) and cleaned my k&n air filter and using lucas fuel treatment. my must be in good condition because the check engine light is not on. Any one have any suggestions??????

Akito · Jan 2nd, 2008, 11:36 AM

It could be your knocksensor. It doesn't set the CEL/SES light on. It's one of those hidden codes. Try getting codes read from your car sometime.

filipinowise · Jan 3rd, 2008, 06:48 AM

okay i will try that, what are the codes for the knock sensor?

Akito · Jan 3rd, 2008, 07:42 PM

P0325.
Source: OBD-II Trouble Code: P0325 Knock Sensor Circuit Malfunction
I am a bit new to this site, so I am not able to provide links to within the forum.
Try the search button.
If you are a DIYer, the knock sensor is extremely hard to get to, especially if your car is a Cali Spec.

06murano · Jan 6th, 2008, 12:09 PM

if you've notice that you're getting poor gas mileage only in the city, but during long highway trips it's about normal...then i would say change out your thermostat. it would affect city driving because your car never get to the ideal optimum temp with a worn thermostat, thus making it run less efficient.