See if anyone experience with this. I know my PCM tuned by Nelson performance. It seem running rich since. I smell gas richer a little in the oil when I drained out to change oil. I asked my friend from dealership just to scan their scan tech2 say running a rich a little. He say it won't hurt. I jus want be safe share with your other opinion. It is normal do that? I just afraid of something can be effect. If running rich would make your mpg bad? My mpg sometimes down sometimes up. From full to almost E on the fuel gauge I made 441 miles. Let me know if you have any kind of like that.

 

A wide band reading would be really nice.. to see exactly what its doin..

Have you cleaned your MAF lately? I know that will make it act weird sometimes.

 

Okay also want see people what your average from full gas to half. How many miles? Mine 268-272 miles on half. Want see your average if you don't mind.

 

You'll never get an accurate MPG that way... You need to fill it up, reset the trip meter, drive it how ever far (at least half) and fill it up again, noting the gallons it takes to fill it up. Then divide the miles traveled by gallons used and that will give you an ACCURATE MPG. It's they only way to know for sure what your MPG is. Just guessing how many miles you get at half or full tank will never get you an accurate MPG!

 

KB do you think I was doing wrong? I did reset 0 at full gas when I filled up. Drove on highway at most it is average closer 272. And From Full to empty almost 441 or 451 I not remember. But I will do that again.

 

440/25 is 17.6 which is normal. how many gallons did it take to fill up?

 

^^^ You need to note how many gallons it too to fill it up and then do the math. My 1/2 or empty and your 1/2 or empty won't be the same

But it sounds like your getting pretty good mileage if your going that far on a tank of fuel.