Short version, since I'm posting from my phone-

I'm getting these codes: P0441, P1171, P1174
Disco is running great, including the idle. I'm not even noticing a change in MPG. I replaced the fuel cap, to no avail. I just purchased the Hyundai purge valve but have to wait for it to arrive, obviously, before I install it. In the mean time, check out these long term fuel trim numbers-

I'm no expert in the matter and have yet to thoroughly research it, but me thinks something is awry, due to the significant different between 1 and 2 (both remain constant; the short term fluctuates appropriately). Any ideas? When I have a chance, I'm going to check for vacuum leaks; there are no obvious leaks and no broken vacuum lines that I can visually detect.

 

The P1171 and P1174 codes have been present for a few months. The P0441 popped up for the first time today. About a month ago, I cleaned the MAF, which I thought worked for about a week but the P1174 and P1171 codes returned. I have about 10 months before emissions testing is required again so I'm in no rush, but the SES light bugs me and I'd like to keep the Disco running for many years to come. Thanks in advance for any suggestions.

 

The P1171 and P1174 lean codes indicate a vacuum leaks. A friend of mine chased them for a couple years before he gave up and sold his truck. Others here have traced the codes to leaking fuel injector O-rings. A cigar smoke test may work; a professional smoke test would be better.

 

Yupyupyup! Check injectors for leakage or replace them while youre in there. Had same codes, only injectors had bad O rings and corrected after replacement. Well, that solved mine.

 

I purchased an O-ring kit on Amazon today. I'll replace them when they arrive and report back with results.

 

Be sure to jump the fuel pump and pressurize the system and check for leaks at the injectors before putting the plenum back on.

 

I always preach diagnose, diagnose, diagnose, so I hope the O-rings do the trick for you. A smoke test would have shown whether or not there are any other vac leaks.

Good luck, and please, please report back to the forum with the outcome. Too many threads end with the results unknown.

 

How full is your fuel tank?

 

Subscribed.

 

Having the same issues, leaning towards O rings as well. Keep us posted on your results.