SERIOUSLY reduced MPG

[Freedom Motorsports]

Those getting that bad mileage and thinking brakes, have you replaced the calipers? GM calipers aren't the most reliable, especially if the brake fluid isn't changed OFTEN. I would completely flush the brake and the hydro boost to ensure that the fluids aren't the problem. Then take the brakes apart down to the caliper and when you take the pads out, take the cap off the master cylinder resevoir, leave the inside pad (engine side) in the caliper and use a large c-clamp to press the caliper pistons all the way back into the caliper. There are two pistons that should be just short of flush with the body of the caliper. Then reassemble the brakes and re-bleed the lines. Then after pumping the brakes to ensure proper operation go for a ride and see if you can tell any difference. Keep in mind that this is with old calipers and you need to save on trying not to buy new ones.

 

[afpj]

Don't forget to consider the O2 sensors. When they start going bad, there is NO code, but I've read the fuel trims will start going out of spec (greater than 10%) if you have a scanner that can give live data.

 

[WildBill]

My bet was O2 sensors. $40 each. Its a cheap test.

Matt, I would think you get you mileage because of the tires and the keys and spacers. Thats just a bit worse than mine and im on 33s.

BTW, I love the white Tahoe, it looks great. It makes up for the mileage

 

[NC_John]

My bet was O2 sensors. $40 each. Its a cheap test.

Matt, I would think you get you mileage because of the tires and the keys and spacers. Thats just a bit worse than mine and im on 33s.

BTW, I love the white Tahoe, it looks great. It makes up for the mileage

+1 on the O2 sensors. They can check your sensors on a diagnostic and maybe have them do a sniffer test on the exhaust to see what your A/F is. If the brakes were dragging enough to cause that kind of mileage decrease you'd smell them and would have ruined them by now.

Aftermarket wheels could be a huge part too (if you have them)- what wheels do you have now and what MPG did you get with stock rims? Aftermarkets (unless they cost a fortune) weigh a ton, add a crazy amount of unsprung weight and eat up a bunch of hp to get going and a bunch of brake to whoa down.

 

[dwmmatt23]

My bet was O2 sensors. $40 each. Its a cheap test.

Matt, I would think you get you mileage because of the tires and the keys and spacers. Thats just a bit worse than mine and im on 33s.

BTW, I love the white Tahoe, it looks great. It makes up for the mileage

Thanks, yea im not complaining about my mileage cause I absolutely love my hoe, Im just comparing to what others with like tahoes with almost the same mods are getting. Seems that I might be getting alittle worse than most.

+1 on the O2 sensors. They can check your sensors on a diagnostic and maybe have them do a sniffer test on the exhaust to see what your A/F is. If the brakes were dragging enough to cause that kind of mileage decrease you'd smell them and would have ruined them by now.

Aftermarket wheels could be a huge part too (if you have them)- what wheels do you have now and what MPG did you get with stock rims? Aftermarkets (unless they cost a fortune) weigh a ton, add a crazy amount of unsprung weight and eat up a bunch of hp to get going and a bunch of brake to whoa down.

I did all O2 sensors, new cats, new exhaust, new plugs and wires, fuel filter, seafoam, radiator flush, trans flush, gear oil change, cleaned AEM filter, cleaned MAF and TB all at the same time and saw maybe 0.5 mpg increase. the last things on my list to try before I throw in the towel and live with it are sitting in my garage which are Efans, intake gaskets and knock sensors. And of course a BB tune.