Just checking to see who has changed their fuel injectors. I just turned 115k miles and thought about replacing them. Thanks for any help.

 

Why do you want to replace them?

 

I noticed I'm not getting as good of gas mileage. They also might be the original ones I believe at 7 years old an 115k miles. Is it regular maintenance to replace these eventually?

 

Your fuel injectors should easily last the life of the car; changing them will not improve your fuel economy.

If you've noticed a relatively recent and noticeable decline in fuel economy accompanied by no OBD-II codes (failing fuel injectors will most likely throw a code of some sort), the first place to look would be the upstream O2 sensor. If you opt to replace it, do NOT use a Bosch unit, the OEM unit, which if I'm not mistaken was Denso, is the best.

 

Yes I don't have any codes thrown by car. I would think if an O2 sensor was faulty it would definitely throw a code. Thank you for that, I will leave injectors alone then.

 

The thing is, O2 sensors tend to get lazy over time and yet aren't quite lazy enough to generate a code. When it comes to throwing parts at an otherwise undiagnosed problem (such as poor fuel economy), the ONLY recommendation most mechanics will make is to change the upstream O2 sensor, or wait until a code is thrown.

 

Thank you for the info. Maybe I will just go ahead and change out the O2 then and see if that helps.

 

That's a good plan.

Just curious, what kind of fuel economy are you experiencing on your 2012 Mazda3 s? Does your car have an automatic or a manual transmission?

 

Its a 2010 Mazda 3s 2.5L Well usually when I fill up my screen tells me about 410-440 miles til empty. And when checking it on my trip odometer I do usually get around 385-420. On my last 2 fill ups, my screen til empty says 345 and 350. And my last tank of gas only got me about 325 miles. Not terrible, but when I was getting close to 400 miles every tank, its def a difference. Maybe I'm just paranoid haha

Its an automatic

 

Lots of Air Conditioning?