lost mpgs

[i-wagon]

So I had some stuff happen and was windering if someone could help determine what may have caused a 5mpg decrease. All in a week I had my stock manifold + cat replaced due to a leaky flex pipe, and replaced my aftermarket exhaust with my factory one, next 3 tanks of fuel I got 22 mpg, and I normally get 27 with the tall tires. Could this be caused by the ecu getting comfused by more backpressure and new cat? I am going to look at my air filter but that's normally a more gradual drop off

 

[drvsdwz]

diconnect the negative and positive terminals to the battery and touch them together to reset the ecu and see if anything changes in the next few tanks of gas

 

[i-wagon]

Ecu. Reset, clean air filter. Hopefully she'll come around. If not I'll look at pcv and plugs ( last 2 culprits for poor mileage)

 

[Chris]

I would not touch positive and negative anything together ever. Ever in a car with tons of electronics. Pressing the brake will do the same thing, but through the resistance of the brake light bulbs.

Anyway, when you had the cat replaced, what about the O2 censor? All plugged back in? Did it get damaged when it was pulled out?

 

[i-wagon]

Work was done at evergreen a couple weeks ago, so I imagine t was by the book

 

[i-wagon]

And no codes on the computer before I reset it

 

[jaKe]

Muffler baFfles + foot into throttle to compensate? I would go two or three tanks before really find average mpg too many variables.

 

[Chris]

Questionable O2 won't always set a code immediately, if at all. It's one of those things that can fail a little bit, but not all the way enough to upset the CEL god.

 

[brighton]

Work was done at evergreen a couple weeks ago, so I imagine t was by the book

Maybe Inski forgot to install the muffler bearings?

 

[drvsdwz]

Subaru dealerships do it all the time. Infact, that's what soa suggests

 

[i-wagon]

Tmissing cnoodle regulator. I'd put money on the exhaust swap, since my factory muffler has less than 1k miles on it. We'll see what happens in the next 2 weeks I suppose, and if it is the o2 sensors they were just put into these headers so they should come out easy

 

[09FXT]

Could just be the gas station supplier has switched over to winter fuel mix

 

[CoupedUpSubie]

Could just be the gas station supplier has switched over to winter fuel mix

This. I loose 3-4 mpg every winter. Mine has gone down a little also. Look into adding some fuel stabilizer or something every now and then. That helps me.

 

[i-wagon]

normally I fun fuel injector cleaner through it every oil change, but haven't recently. I'll have to get some

 

[inski]

Maybe Inski forgot to install the muffler bearings?

I checked the halogen oil and topped off the blinker fluid. I found a loose nut behind the steering wheel. He done his own muffler bearings so I'm not to blame fer that.

 

[i-wagon]

Don't forget the short circuit between the drivers seat and steering wheel

 

[CoupedUpSubie]

normally I fun fuel injector cleaner through it every oil change, but haven't recently. I'll have to get some

I use a product called K100. It has helped outboards, atvs, trucks(diesel and gas), and cars.

 

[K3rn]

maybe your right front directional is on the left side...

 

[Matt]

I just had my front o2 sensor go bad...horrible mileage....made the car run like absolute crap...actually shot a fireball once, but it also took 3 weeks of this to finally fire off a code....damn fuel/air ratio sensor!!!!