For the past couple days my engine light has been on and I have been trying to figure out whats wrong with it before I take it to get looked at. Well my truck is a 2003 Dakota Quad Cab 2wd with the 3.9L V6 with only 31000miles on it. Well Im only getting around 14 mpg on the highway and that was even before my 20s. Im thinking that the truck is running rich because the exhaust tip is black inside and just around the tip and I guess this would be why Im gettin 14mpg highway. But would this trip the engine light and if this is the problem would it just be that I need a new fuel filter???
Thanks in advance

 

if you can get your hands on a scanner try to see what code its throwing. it sounds like one of your o2's might be bad, and thats why it would be running rich

 

Unless you've got O2's in both collectors it would be the upstream O2 that is bad. The downstream one just tells the ECU that the cat is working properly, the upstream tells the ECU what the a/f is.

 

You guys were exactly rite just got it fixed and it runs a whole lot better. Thanks for all your help.

 

Well thought it was fixed but the light came back on today[:@] and idk what it is now. It is gettin better gas mileage im gettin 17 mpg now which is up from 14 after the o2 sensor but idfk whats wrong now. Anybody have any ideas??

 

Go back to what DodgeRam808 said... I know AutoZone will check "Check Engine" codes for free and can give you the code and a basis for where to look for the problem.
If you know the code, you aren't just shooting blindly at a problem.
I know that my truck dropped mileage from about 15 to 12-13 due to me only driving it to and from work... and nothing is mechanically any different, so that isn't always an indicator.
Find out the code and let us know... then we can help more....

 

The engine light came on in my RAM but it was blinking...From what I was told if they are doing that its TROUBLE!!!!! man was it ever...I had a mess. One of my injectors had fouled up dropping #8. Moved that same injector to #6 and it did the same thing..I had to replace all 8 injectors..I have a long post on here about engine light problems. I replaced everything. O2, CAD, Crank Sensor, then when it got technical on me. I had to bend over at the Dealership. I even replaced the CPU up on the firewall..That engine light blinking cost me over 2500.00 bucks. The CPU was my fault..but only cost around 325..The rest was those injectors and sensor replacements..She runs like a top now..
GOOD LUCK

Ronnie