I previously had issues in my 1999 ford Ranger xlt 3.0l Flex Fuel (vin v) 2wd automatic Transmission running rough when starting but only at season change when the content of ethonal changes in standard gas. I did a serious tune up of the truck that I just finished with a waterpump replacement. Everything test out working and in good condition except the new Flex fuel sensor I paid $750 for is leaking about a gallon of gas every 10 minutes. I did notice that the fittings on it that screw into the top of the sensor were screwed all the way in when I removed the old sensor. When I installed the old fittings in the new Flex Fuel senor I was only able to screw them in about 3/4 of the way. I barley have the strength to tighten them any more then they are, even though they are only 3/4 of the way in the hole. I am also fearing damage if I tighten them more than they are. I could get a breaker bar and tighten them more but I am afraid to do that. I used a 19 mm box wrench that is about 10 inches long to tighten them to where they are now. A 24inch breaker bar would help in continuing to tighten them, but again I am fearing damage if I do that. I would like to avoid buying another $750 sensor if I can help it. I bought the sensor from Summit Racing online: https://www.summitracing.com/parts/smp-ffs2

Can anyone tell me if I did something wrong or maybe I just need to continue to tighten the fittings futher than I have?

The new fittings that came with the new sensor are not going all the way in the old sensor either, without also applying a great deal of torque to them as well. I can not really tell any difference between them and they seem the same. Not sure why they will not screw in all the way or why the new senor is leaking. I am able to start the truck and it runs smooth at an Idle and will warms up to operationg temp. It just looses 3-4 gallons of gas from leakage while doing it. I have no other issues with the truck at this point. I just can not drive it do to it leaking copious amounts of gas from the Flex Fuel sensor.