I just got a '92 F150 4x4 with a 5.0L engine. The exhaust system has been replaced and headers installed but the owner said that the oxygen sensor(s?) had not been installed.

I didn't worry much about it since this will primarily be a utility vehicle, but won't the O2 sensor be required to get good fuel economy? (I haven't driven it enough to even find out what the existing fuel economy is).

Do you think the milage will be dramatically worse than stock if I just leave it alone? (It seems to run okay - I just don't have much for comparison).

If one or more O2 sensors are necessary, can anyone give me some information on instalation with headers? (Or point me in the right direction, I haven't found much yet on my internet searches).

Thanks.

Martin

I didnt think EFI could run without the O2 sesors? Your headers should have a bung welded into the pipe that the sensor will screw into. If not then get two O2 bungs and get them welded in and get two O2 sensors

For your year truck it should have a speed density fi system with only have one O2 sensor. Here is the picture of my Bassani y pipe that I put on my 94 bronco. If you look right before the two pipes merge there is a small crossover pipe. That is were the O2 sensor screws in.

http://www.supermotors.net/getfile/475651/fullsize/100_1565.jpg

yup just one O2 sensor. and it doesn't run right on a stock computer without the O2. it will be bad and should go into limp mode till you fix it.