April 22, 201114 yr 97 Leggy 2.2 auto tranny with 193,000 miles. I've been getting increasingly worse mileage the past 6 months (from 29ish overall to 20-22 MPG). The following have been addressed: New 02 sensor, fuel filter, air filter, oil change/w filter. So, WTF? Plugs (NGK) are recent, I checked them and re-gapped them, wires are kinda old, no idea on EGR, and PVC valves. Ideas, comments, funny embarrassing stories?
April 22, 201114 yr Get a bottle of SeaFoam. Put 1/3 in the gas, 1/3 in the crankcase and 1/3 into the vacuum intake. It's smoke like a mofo and get tons of carbon out. Change the oil about 50 miles later and reclock the MPG.
April 22, 201114 yr I would definitely replace the plug wires--use Subaru OEM only. Would also replace the PCV, plus clean the hoses leading to it and check them for splits & cracks. Sorry, no embarrassing stories, none that I'll tell here anyway! Good luck and let us know.
April 22, 201114 yr No codes? CEL works? ECT sensor is a common failure, tends to cause driveability issues but could also lead to poor fuel economy. Which O2 sensor was changed? Front or rear?
April 22, 201114 yr Author No codes? CEL works? ECT sensor is a common failure, tends to cause driveability issues but could also lead to poor fuel economy. Which O2 sensor was changed? Front or rear? Front was changed with OEM. The car actually runs well, a little "off" but not anything super noticeable, just crappy mileage.
April 22, 201114 yr Author Get a bottle of SeaFoam. Put 1/3 in the gas, 1/3 in the crankcase and 1/3 into the vacuum intake. It's smoke like a mofo and get tons of carbon out. Change the oil about 50 miles later and reclock the MPG. Getting some today.
April 22, 201114 yr Check your knock sensor as well, I have heard that it can cause poor fuel economy not sure on that but mine is getting better mpg since the replacement, odds are yours has never been replaced and its most likely cracked, RockAuto has OEM ones for about $50. I'd also look into your coil as well, they tend to not fail but mine was biting you when it was touched, after the new one no probs and noticeably better fuel mileage. When I changed out my PCV valve on my 2.2 it was very gummed up and so was the hose leading to it, I just used some brake cleaner and cleaned out the hose and dropped in the new valve and my idle smoothed out greatly. Odds are you just have some dirty old part that either needs replacement or cleaning(EGR).
April 22, 201114 yr No codes? CEL works? ECT sensor is a common failure, tends to cause driveability issues but could also lead to poor fuel economy. Which O2 sensor was changed? Front or rear? ECT?? what is that.
April 23, 201114 yr Author SUCCESS!! It would appear plug wires, PCV valve and a can of SeaFoam (holy god, what a cloud of nastiness) has done the trick. Primarily the wires I think, the old ones were pretty haggard. Thanks for all the input, folks!
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now