92cobra

uhhhh so suddenly i wake up one day, get in my car and it decides to get TERRIBLE gas milage.

last time i checked i can get 270 every tank with my foot in it, 300 if im relaxed.

Now i CANT get to 200 to a tank.

How the hell is this possible? Just randomly one day happened. Im not leaking any fuel either.

The fuel filter, along with the rest of regular maintence was done about a year ago. The car is putting out 3 codes and im thinking this could be the issue. I forget what the codes were, but 2 were EGR codes and the 3rd was something like "fuel out of range" or something, which would be caused by the egr codes.

Could the egr issue suddenly decrease my milage by not 20, not 50 miles, not 80, but a flippin 100miles to a tank?!?! Also, I have filled up twice, both 89 octane, and got the same mpg results, right about 200 to a tank.

Considering the other day i filled up when i was at 289miles im a little pissed lol.

edit: car is an auto 91gt, greensteak want me to take a picture of my window for you, it feels light. <3

mjr46

need the complete list of code.......egr if it is stuck partially open will cause a lean condition but a noticeably rough idle ..if you have no rough idle than I'd rule that out...but a coolant temp sensor bad and or mass air meter dirty or bad play a significant role in fuel calculation tables as well as 0/2 sensors..need a complete list of codes and we'll go from there

92cobra

i will run the codes later on today, and grab the 3 of them. The idle is absolutely perfect, and the o2 sensors are pretty new. I havent cleaned the maf for a few months so i will do that now, but i highly doubt that it would cause a 100mile difference over night. But im sure it will play a roll.

As far as a bad coolant sensor, I didnt even think of that, thanks for the tips. Also, if you read the post i just made, at the top for some 16yr old kid, you will have a good laugh mid way about udp's. =P, thanks for the help and take care, glad to hear you had a good time in arizona.

Jfsram

I would address all the code issues before I questioned any fuel mileage issues. Most likely related.

Cold weather accounts for some loss too. Not the 100 miles you mentioned but maybe 10%.

mjr46

speaking of the codes did you ever get them ?????