1990 ramcharger, and for as long as i've owned the truck the O2 sensor has been removed leaving a hole in the cat. So nothing is hooked up where the 02 sensor has been but the truck runs fine and no CEL. Since than i've done a few things to engine, dual exhaust, fuel filters, new plugs, wires, cap, rotor, k and N open air element. Im stilling getting 10MPG even while driving average, could this be due to the o2 sensor missing?

 

The 02 sensor should be in the drivers side exhaust manifold...

Is the hole in the cat threaded? Did it have an air injection tube on it that is missing?

Plus without the sensor you would have a check eng lamp on and it would not run right.

 

i would guess without the o2 sensor the computer is going to run the engine rich which is going to cause crappy gas mileage.

 

Well is what i was thinking, however not sure but i think its probably the air injection tube that was never plugged in. I've removed the air pump anyways because it was annoying, Yeah no check engine lamp. The truck runs fine, not as responsive as my 96 multi port fuel injected dakota but just ok. I should mention that in rainy or wet weather when i try to gas it the truck stalls occasionally. Could this be injectors? For the record i've run like 3 cans of seafoam through the gas which seemed to help i guess but still stalls somtimes.

 

i would guess the stalling could be related to the o2 sensor not being there. usually if a vehicle is running rich it take less to stall it.

 

Do you have oversize tires on the vehicle or is it all stock?

Have you checked the codes?

 

they are performance tires from a newer dodge. Bigger tires probably...yes 17" rims on 275/55. So they are heavier and wider than stock...i guess this would be why?

 

I was wondering if you had put larger tires like 33's or 35's on it which would change your final gear ratio and kill your power and fuel economy.

Edit; it would also alter your odometer\speedometer which would affect your mileage calculations as well.

 

those tires are pretty much the same size as the stock so they should not make much to the odometer. there only about 0.03" difference in size.

 

yea except alot wider and heavier...Which wouls effect gas mileage aswell than huh? Also i should mention the tires vibrate the whole truck at 55 to 60 mph ive had them balanced and they were out but they still vibrate i've been told the tires have abnormal wear on them which could be the reason for vibration.