Really bad MPG, need help trouble shooting.

[SuperAkuma]

2011 Legacy 2.5i with 6MT. Everything is pretty much stock.

Bought the car brand new. It has about 190k on it. No major issue with the car. Oil change religiously. Need to do the timing belt soon but everything else is up to date. Engine bay is leak free, no oil spots beside where the PCV was at.

 

Until recently I had great/good MPG. 30mpg on freeway and in the city about 23-25mpg easily.

 

I've always reset the MPG after every gas refill, just a habit. Sometime fall of last year I noticed that my MPG was pretty bad. I do mostly street driving to work and home. I work about 5 miles away so not much of a drive but I do work at 4am in the morning.

 

I've noticed that I wasn't even getting 20mpg, more like 18mpg or so on the street, rarely over 20mpg. It has been about 6 months now that is like this. My driving habit has NOT changed for the past 2 years. With gas price over $5.50 here in Cali, this is something that I really need to figure out.

 

One thing that I did noticed was when idling on cold engine, it is about 1,500RPM. Not shaking or anything. When the engine is warmed up, it settles to about 800RPm or so. Besides that the car runs perfect.

 

CEL is NOT on. The only code I pulled is U0110 which is related to Anti-Lock Brake. Not sure how long that has been on.

 

-It is NOT my driving habit, nothing changed for 2 years

-Not the tires

-Engine filter changed

-Spark plug changed

-MAF cleaned

-Throttle body cleaned

 

 

What is the next step to check?

Edited May 17, 2022 by SuperAkuma

[Fabsx]

Worth checking.. something people oversight. Check your brakes. They could be sticking, seized caliper or slide pins.

 

 

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[SuperAkuma]

Worth checking.. something people oversight. Check your brakes. They could be sticking, seized caliper or slide pins.

 

 

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I've asked a lot of people and no one said that. The funny thing is doing the brakes was the last thing that was done to the car.

 

I've never done brakes myself but I know what the components are. Is there an easy way to check to see if the caliper are seized?

[creep_nu]

just drive for a while...when you're done put your hand NEAR the brakes, do not touch, and feel if one's exceptionally hotter than the others, if so that's your problem child and it needs to be checked. how long after getting the brake work done did you start noticing the bad mileage?

[Fabsx]

I've asked a lot of people and no one said that. The funny thing is doing the brakes was the last thing that was done to the car.

 

I've never done brakes myself but I know what the components are. Is there an easy way to check to see if the caliper are seized?

 

 

If you can move the calipers piston in, your good

If the slider pins are stuck, they wont move in and out of the caliper bracket. Typically it’s the one with the rubber boot end.

 

Edit; given your mileage and if your going to diagnose the brakes. Flush/bleed the brakes with new fluid to justify being near the brakes again. Crack the bleeders open while to verify each caliper isn’t seized. I have issues with the slider pins seizing and sticking causing abnormal wear. I just went with brembos after that since they dont have sliders

 

 

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Edited May 17, 2022 by Fabsx

[Pleides]

Just did front calipers on my girlfriend's Grand Cherokee. Shop found that one of the pads on the right front were super low on material while the other (I think the inner pad) had a lot more material left on it. It caused them to squeal at odd times, like cornering right.

 

So I guess check the brake pads.

 

Perhaps it could be carbon buildup or bad plugs?

[SuperAkuma]

Inspecting the front now. Both top sliders moves fine, the bottom one is frozen. Had a really hard time pulling the pin out. Got it out, clean and greased. I wasn't able to put the bottom one back in. After doing some research it seems like the rubber gets swollen up and will prevent it from going back in. Many people said they just removed it. Did that and it went back in with no problem. Anyone else had this issue? If you did, did you remove the rubber as well or did you just get a new slide pin?

[Fabsx]

Inspecting the front now. Both top sliders moves fine, the bottom one is frozen. Had a really hard time pulling the pin out. Got it out, clean and greased. I wasn't able to put the bottom one back in. After doing some research it seems like the rubber gets swollen up and will prevent it from going back in. Many people said they just removed it. Did that and it went back in with no problem. Anyone else had this issue? If you did, did you remove the rubber as well or did you just get a new slide pin?

 

 

Get some good heat in there, the caliper bracket and heat that up vs the slider itself.

It’ll heat up enough to where you can twist the slider out.

If you’re careful enough, you can reuse the sliders and get rid of the rubber inside. I just normally pack it with grease.

But to make it permanent, get new sliders, clean out the bracket inside with a wire brush to remove rust and your set.

 

 

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[creep_nu]

if you use the wrong kind of grease(petroleum based vs silicone i believe...) the rubber swells. that little collar is just to help squealing as far as i know so you're fine not having it in there...mine definitely weren't the first time i did pads...kit came with new hardware last time i changed them so i reinstalled...no difference.

[coco26]

I too was told you can get rid of the rubber when my slide pins were sticky, but taking it out made my calipers clunk around on every small bump. I got fresh ones and solved the noise with no sticking issues.