Jump to content
Ultimate Subaru Message Board

Recommended Posts

I have a 99 OBW, 2.5 auto. It has 187,000 and starts good and runs normal. I’ve been getting 12 MPG or less in all around town driving. It used to get more like 17 MPG around town. This has been going on for awhile, not just a new thing with cold outside temperatures. From reading, this could be lots of things, including mass air sensor, air or water temperature sensors, or bad injectors among other things. Is there any preferred order to check into these things? Does anybody have any good troubleshooting methods?.

Link to comment
Share on other sites

I would start by knowing your basics are good.......... How good are the spark plugs, plug wires? Has the EGR valve been cleaned/changed? Does motor warm up normally? If not, the water temp sensor or thermostat may be bad. Any of these things can cause poor mpg.

Link to comment
Share on other sites

Plugs and wires may be a good place to start, They were done about 45,000 miles ago with genuine subaru parts. The EGR moves when you blip it and the EGR ports were checked clear in the last year. The temp gauge comes up pretty quick and heater works well, but the water temp sensor for the computer could still be bad? Appreciate the insight.

Link to comment
Share on other sites

Definitely replace the front O2 sensor with an OEM unit. I think the 99 came with a Bosch. They are different parts for auto and stick. should cost around $100 but at 14mpg you it will pay for itself pretty quickly. I would also change the plugs too.... they might be a little black and sooty

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...