I'm getting horrible gas mileage all of a sudden after swapping injectors. My wideband is going nuts and I'm seeing as high as 16.0 afr at certain spikes. The truck overall runs fine, but has no ***** when accellerating on the highway. When I hit the throttle in park, it will jump down to about 12 afr then when I let off it will spike to about 17 for half a second.

This all started after I swapped from 42# injectors down to 31# injectors. I did copy the injector settings over from an 8.1L truck and I have run 8.1L injectors before and tuned for them with no problem.

Anyone have any ideas? The truck went from getting around 20-21 mpg on the highway down to about 14.

Could it just be random that my o2 sensors failed? I don't exactly have the cash to replace them if I don't need to.

 

I would pull them and put new bottom O rings, sounds like one is cut. I had similar problems, except I couldnt hardly get my wideband to read rich at all. oil them up good when u stick them in the intake

 

Perhaps the new injectors are clogged

 

Pulled the wires on each injector individually and the #8 cylinder injector didn't respond when I unplugged it. Pulled all the injectors and tested each with a 9volt battery and sure enough the #8 isn't injecting fuel. I tried soaking it in brake cleaner and kept testing it but no luck. I can hear it pulsing but no fuel is coming through. Ordered a new injector online and it should be here.

I'm going to throw my 21# 1999 fuel injectors on there and see if it makes a difference. I have a feeling things will be back to normal again.

 

**** that sucks