I've got a 98 outback with 82,000 miles that is getting poor gas mileage. I had the headgaskets done a few weeks ago along with timing belt, waterpump and cam seals. I am getting 22-23 mpg on the highway between 65-67 mph. I plan on changing out the front O2 sensor as antifreeze can kill it pretty quick. Is there a brand that works best in these cars. I have found a denso and NGK/NTK for about 65-70$ and an sng as well in the same range. I am leaning toward the denso but wanted to get some opinions from those smarter than me.

 

Thanks.

 

Matt

Well, I'm probably going to get burned by other members who are going to respond that you should by the Subaru branded OEM.

 

But I've had good luck with the Denso's, typically getting 100K to 140K before replacement.

 

http://www.sparkplugs.com/more_info.asp?AAIA=1305548&pid=2149

 

This retailer also carries the Bosch and NGK brands, just go back and reselect the brand preference.

+100 for OEM

Thanks, I ordered it from sparkplugs.com yesterday afternoon, before I saw people had responded. I went with the NGK/NTK. I'll let everyone know how it works out. I hope it helps my mileage. can't hurt right.

changing the egr valve may help gas milage too

Just an update in case someone is searching for this down the road. I went with the NGK and it was a direct replacement. The hardest part was grinding off the bolts that were rusted together on the heat shield. Once that was off took about 5 minute to replace. I disconnected the negative battery cable, unplugged the oxygen sensor, unscrewed it. Takes a 22mm wrench and screwed the new one in. Plugged it in and connected the battery cable and she ran great. No check engine light or anything. I put the heat shield back on with new bolts, lubed up with anti-sieze.

 

MPG on the last couple tanks is 25.3. I gained a couple mpg, and can live with 25.5 mpg on winter gas. Hope it goes up soon!

Your improvement sounds about right. The O2 sensor from bad to good should yield about a %10 improvement in mpg.

 

Should be good to go for the next 100K.