Things to check for low mpg

[Big Mama]

I just bought a 2003 Yukon Denali. Check engine light came on.

I checked the previous owners service records he gave me. Previously reported as a faulty map sensor. Which is about 400 dollar fix. I have now found out the shop that checked it failed to diagnosis the problem correctly. Instead it was a pcv valve that had not been changed out in years. Now the fuel milage is much better no rough shifts either. Hope this helps some.

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It’ll help me

 

[swathdiver]

It’ll help me

Do we have the same pcv system as he does? I think ours is part of the valve cover, no moving parts now?

 

[BlueCollarTahoe]

im gonna check and replace this next if it is indeed replaceable.

 

[Big Mama]

Do we have the same pcv system as he does? I think ours is part of the valve cover, no moving parts now?

Correct the 6.2 is on the valve cover with a tube. Cheap way to get a little better mileage. Under $10 for the valve and under 20 including the tube. Also recommended changing the valve cover gaskets and the purge valve. I’m guilty and need to change both. Why wait for a problem for $20

 

[swathdiver]

Correct the 6.2 is on the valve cover with a tube. Cheap way to get a little better mileage. Under $10 for the valve and under 20 including the tube. Also recommended changing the valve cover gaskets and the purge valve. I’m guilty and need to change both. Why wait for a problem for $20

So the valve is replaceable or are you saying to use the old style? What purge valve? Sorry, I'm a little slow today.

 

[BlueCollarTahoe]

this isnt replaceable is it? looks like its built in there:

 

[Big Mama]

I found a good video on YouTube showing how to replace the purge valve.
If this link doesn’t work type in 07 Denali 6.2 purge valve

 

[sonic_the_hedgeh]

Make sure you change the pcv valve. Mine is at the back near the firewall on a thick hose.
There is a YouTube video that is really good.


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Sorry typed that wrong I have a 2004 Yukon. 6.0 engine. I get chappy mileage as well. Going to have to change that purge valve

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[bottomline2000]

I just recently replaced my front brake calipers and wheel hubs. I noticed some uneven pad wear on the front. My wheel bearings didn't make any abnormal noise, however, after swapping everything I have noticed a slight increase in my fuel mileage like 10%.. There are so many variables that could impact mileage..hopefully u find the problem.

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