So...I've had my Dakota for about 6 years now...believe it or not, but it was only til this weekend where I actually drove it over 200 miles. That was a mistake...

I was confident that I was able to get 280+ miles to the tank, but did that happen? No. My MPG was WORSE than my city driving, which is now consistent at 13.5 - 14.5. My truck managed to pull 9 - 11 MPG. Yeeup...after my trips to the gas station, the CEL came on. P0171: System running lean. I managed to get a 10mm wrench at Iowa and reset the computer...didn't fix it.

So now...I don't know where to begin. I've noticed RPM fluctuations when I was steady at the pedal. Any ideas?

 

damn, ummm i would start with IAC and 02 sensors. were you getting like 230ish miles on a tank then? was it pinging at all? check fuel pressure,

 

Nope...I was getting under 200 miles to the tank. I don't think it was pinging, but I did in fact notice rough idling after the trip. The exhaust sounded more funkier than usual. It had more of a growly tone to it. It's obvious to me that something is not regulating correctly with steady ~2500 RPM @ 80MPH.

Good thing for the keg this weekend. I would have gone ape **** seeing my credit card being swiped more than it should be...

 

ouch dude, running lean isnt good for the motor. start with the fuel pump and o2 sensors.

 

Depends on your setup/tools etc. Can check pressures of fuel, but run the ODB code/s and see what happens.
Id take time to do a nice little overhaul...tune up/refresh of a lot of stuff. Plugs, sensors, TB clean (upgrade ) or who knows. I've got some toys coming, and need to save up for one more before I take the truck down for a weekend..Now my muffler connector rusted through again (homemade, damn tubing always fails...) so it might be more than one thing...

Curious, what town you in? I have family up north of Chicago..

 

Yea....I know =\ I was getting a headache thinking about it too much. The pre-cat sensor has been replaced...the post-cat has never been replaced, not sure if the post-cat matters. My friend has a pressure tester, so I'll get that tested tomorrow.

The truck got new goods earlier this year. Plugs and Fastman TB have been installed. Everything seems to run fine under normal city conditions. Maybe the pump is going...won't know until I get it tested.

I live in Palatine, by the way.

 

There is something HORRIBLY WRONG then! I drove from indiana PA to snowshoe wv (235 miles) on just a hair over half a tank!

 

vacuum leaks can cause a lean running condition

 

Yea, that's exactly what I was pissed about. I know damn well I could get at least 17MPG. Terrible waste of money. At least the prices in Iowa was $3.50 per gallon as compared to $4.20 here. If there's issues and if the pressure test proves to stink even at low load, that will explain a lot of the MPG+Power problems I've ever had. Can't wait to get it done.

By the way! Our fuel filters are in the gas tanks, right?

 

Yup filter is in the tank! Sucks, I know.

I can usually get 300 miles before the gas light comes on under pretty much any driving conditions. If you're going through a lot of extra gas, doesn't that give you the idea that it's running rich, not lean? The ECU is telling the engine it needs more fuel.. a lot more fuel. For whatever reason. That doesn't sound like a fuel pump issue to me. Sounds like a MAP sensor to me. The ECU thinks it's getting more air than it is so it wants to dump fuel into the cylinders. Or possibly a o2 sensor doing the opposite.

It doesn't sound to me like it is running lean. Not sure why the CEL thinks it is...