Lately I have noticed my mpg has been lower than usual and engine power has been sluggish. It has always been like this ever since I purchased it, but the problem seems to be getting worse, even after the HG job a year ago. The truck also smells rich after parking it into the garage despite new catalytic converters.

I have my ultra-guage set up to monitor the fuel trims, and the LTFT for both banks is maxed out at 24 (throws a CEL every so often when it goes above 25), the STFT is about -7 ish when driving, -25 when at idle. I have searched high and low for vacuum leaks and have found none. I also run a bottle of fuel system cleaner every oil change, but it hasn't helped at all. Mass air flow readings on the UG seem fine too, as well as the coolant temp. sensor. I would like to know if this is caused by something simple like a bad MAF or oxygen sensor, or something bigger a faulty ECU.
Prior to me owning the truck, the thing had had tons of vacuum leaks due to broken lines. In fact, both crank case breather lines were broken in half. Those have since been fixed, but shouldn't the ECU return the LTFT back to normal after it has realized there is less unmetered air in the the system? If anything, it ran better and didn't throw CEL's with the broken vacuum lines.
Any help?

 

I'm not sure how you reset the ECU on these trucks, but if you can, that would set the LTFTs back to zero so you can get a fresh start. Maybe a battery disconnect for an hour or so. Another thing is a guy on here reported good results with a new MAF off of ebay. AS a matter of fact, I bought one. It was around $80. I kept getting P0178 - I think, but it was max fuel richening, and I had checked high and low for vacuum leaks. So far, so good. Wait, here is a link to the post -

https://landroverforums.com/forum/di...-sensor-62437/

 

Funny how things turn out... are you talking about my ride here?
No, seriously, lift the load bay carpet and remove the round black access panel to the fuel tank... Water sits in the recess and rusts the fuel line.
I just cut the bad part off and rebuilt it with a length of FI line and a short piece of fuel tubing (I flared the ends so the hose doesn't slip off). I used about a foot of tubing, with a single coil around the fuel pump opening to have lots of room to work.
While you are in there, spray some zinc primer on the rusty bits... it will stop the rust.
Zinc primer is not compatible with regular paint, either use water based paint or regular primer before painting.
I normally spray the brake rotors (not the braking surface) with grey zinc primer.

SD

 

So you are saying it could be a rusty/clogged/bent fuel line? I will have to check it out when I have the time...

 

Still struggling...MPG sucks right now.

 

Getting p1176 and p1178 frequently now.

 

Check your electrical voltage. There has been reports of weak battery / system voltage negatively impacting sensor and ECU performance.

 

Funny thing bout the 1178 ... I had it thought it was bad fuel pump (which was partially..)

Mine just recently returned, and when I was doing somethin w/ the truck i noticed smelling fuel again in the back.. The lil 3/4in fuel hose is leaking again, causing the pressure in the tank to be lower and i suspect that is triggering the 1178

Stupidest thing, but just for grins check your vapor recovery hose.. Also after its been running do you get a blast of air when you loosen the gas cap?

 

I have been dealing with somewhat of similar issues only i just have horrible mpg in my 98 D1. Just recently had valve cover gaskets and Oil sending unit replaced, Fuel pump and thats it for my first year of owning mine. But yet i still get horrible millage outta her. Struggling to figure out why im getting about 12-13 when i should be getting more

 

I was previously getting 13-14mpg, now it get about 10!