I keep getting these codes P0174, P0171, sometimes i get both, sometimes just one or the other. It seems i mainly get them on the interstate traveling at 70 or while getting on the entrance ramps. But they have came on at other speeds as well. O2 sensors, all exhaust gaskets, and cats have been replaced. IAC and MAF has been cleaned. Ive searched for a resolution. At this point im thinking MAF, or some type of vacuum leak but i have sprayed starter fluid lightly around openings. Any ideas or help would be great. Thanks in advance.

 

I am experiencing the same difficulties. To attempt to track down my vacuum leak I did a smoke test. Theoretically, It should show you where your vacuum leaks are on the engine. I found out that my leaks are down lower, potentially in my fuel injector rings, but I couldn't EXACTLEY see...

Either way, it was easy and worth a shot! Here is the link:
https://landroverforums.com/forum/di...s-cigar-54235/

 

Ill try it in the a.m. thanks!

 

Well i tryed it and it actually worked. Some smoke was coming out where the brake booster goes into the upper intake. Ill have to get another fitting though as the red plastic lock fitting cant get any tighter. I wonder if there should be a gasket or something inside of that fitting?

 

I am glad that worked well for you!