Poor gas mileage question

[Project 77]

OK I am getting terrible mileage out of my car...like 125-150 miles on a tank of gas whereas I used to be able to squeeze almost 245 out of a tank. My car has a motorsport X cam, and initially it had 24 pound injectors, well i went back to matching 19 pound injectors and stock mass air meter, since then mileage is bad.Still has stock 3.27 gears, O/R H pipe and SLP exhaust.

I should Add that when it's idlling you get a real strong gas odor from the exhaust

 

[urban96]

maybe you have some bad O2 sensors or you forgot to plug something in

 

[chrismillion]

sounds like the o2 sensors, have your car put on a scanner to see if any codes have been picked up. that will explain your bad gas mileage and the smell, cause your car is probably running lean. one other thing is the charcoal canister can make your car smell of gas fumes, but i don't think it affects your gas mileage.

 

[Project 77]

where are the O2 sensos on a car with an O/R H pipe?? I thought they screwed into the bung on the old stock H pipe, my H pipe didn;t have a place for them and I think whoever did my exhaust just taped them to the underside of the car maybe????

 

[HISSIN50]

where are the O2 sensos on a car with an O/R H pipe?? I thought they screwed into the bung on the old stock H pipe, my H pipe didn;t have a place for them and I think whoever did my exhaust just taped them to the underside of the car maybe????

updated list of things to check. pull codes and then find your O2 sensors. no one would be so inept as to tape the O2's up. naw. ok, maybe.
good luck.

 

[mystang94gt]

where are the O2 sensos on a car with an O/R H pipe?? I thought they screwed into the bung on the old stock H pipe, my H pipe didn;t have a place for them and I think whoever did my exhaust just taped them to the underside of the car maybe????

The O2 sensors are right where the h-pipe meets the headers....

Another thing in case it isnt the o2 sensors, I was having a similar problem with my car and came to find out one of my spark plugs wasnt gapped correctly (it was almost pinched closed) resulting in one of my cylinders misfiring. That made the gas milage horrible and the smell of gas was really strong since there was a lot of unburned fuel going through the exhaust.