Let us know if this helps your milaege. My car averages about 15-16 mpgs after all the mods but I rarely drive it so don't care much. I have my rear 02s which I removed many years ago, I may swap those with for my font ones. If your tune is off it may have caused your 02s to get fouled, in which case your new ones will get fouled too. I may pick up a new air temp sensor myself.

 

Yeah tomorrow i will be mailing my pcm to frost to have everything fixed while waiting on my o2 sensors and iat sensor to come in.

 

15-16 mpg in the city is normal. I wouldn't expect more

Really if you intake air temp sensor is going out you would have the symptoms of a bad maf since the car isn't getting good temperature readings.

The factory temp sensor is plastic with a tiny resistor exposed. The replacement ones are brass and much better. It's pretty easy to damage tr factory ones when you put a lid on the car

 

Well waiting on the new o2 sensors to come in and since I had the car in the air to install my CF Splitter I went ahead and pulled the old o2 sensor. The left is the driver side and the right is the passenger side. They both look like stock denso's but the passenger side looked like someone had messed with it because it was loose and someone had cut the blue safety pin. The tips on them have the white burning residue on it like you would see normal on spark plugs but the outer ends are like pitch black as you can see in the picture, my guess is from running so rich. Anyone else got any good input as to whether or not these sensors look normal.

O yeah and passenger side post-cat sensor is a bosch it has been replaced driver side post-cat is still a denso. I know our PCM's hate bosch so have a feeling its going to have to be replaced also.

 

Decided to post the final results on this outcome for further searchers. After replacing the upper o2 Sensors with stock denso's (not bosch) and having my computer tuned by Frost tuning the car seems to be producing much better MPG. Today I drove her 120 miles round trip to the dyno today and at the end of the day I have a little over half a tank still. I know 120 seems low for half a tank but you have to imagine the four pulls I did on the dyno into account, I could almost watch the gauge drop when I was dyno'ing it lol. They also performed an AFR reading on the car while it was on the dyno and all the AFR Checked out fine during idle/wot. So either it was the old stock o2 sensors or possibly tuning on the PCM. I also had my rear O2 sensors deleted with the tuning but I believe the biggest help was replacing those two upstream.

 

I am about to try the same thing. I went to the track last week and apparently fouled a plug. I changed those and fixed my missing under load problem. Now I am almost at a half tank on 68 miles. I ordered o2 sensors THANKS for the heads up on Rock Auto. I was about to over pay at Auto Zone. Ill post up my results.

btw...what did she dyno??

 

Sounds like your much happier now. Glad things worked out, Just for another baseline, I get about 50 miles per quarter tank on the fuel gauge in the city. I got a question to, how much the frost tune cost? Feel any difference performance wise after the swap and tune?

 

I pulled a 337 hp on the dyno 370 torque. Umm... I really cant say that I did feel much with the tune from frost but he did fix all my problems and on the dyno my A/F ratio was perfect so he got it on the spot (plus mines an M6, I feel auto would benefit more). He got rid of my check engine for deleted air and deleted rear o2's so I feel it was worth the $150. But, you wont find it much cheaper than that because for him to buy a license for each car for tuning it runs around $100-120 then the rest is his profit. I can't stand having a check engine light on in a car. My wifes evap system just crapped out and its going to cost me roughly $200 to replace just to get rid of that check engine light but I cant stand looking at that light lol.