Sorry for the long post, trying to summarize a recent long road trip I took in my LR3. Spoiler: All of a sudden my LR3 is running the best it ever has, since I've owned it, and I have no idea why! (well, an idea, but can't confirm).

Problems: horrible performance since the year ago that I bought it, 163k miles, front suspension issues, no engine check light / but sometimes rover specific errors / notices about transmission (not displaying gear number on dash when in manual mode), etc. you know, the usual quirks. Guessing vehicle was used for nothing but short errands and might be carbon'd up. Had passed emission tests just fine.

Maintenance: full seafoam gas / throttle body / oil treatment, then an oil change, new spark plugs, new MAF, and new front upper/lower control arms, Timken hubs, and new tie rods. Performance a little better, but still poor. Suspension wise, drives like a dream. Air suspension has always worked just fine.

Did a 3500 mile round trip to Elkhart IN to pickup a new cargo trailer (3150lbs empty, but lots of wind resistance)... coming home had to have AC system purged/recharged (mechanic said his equipment detected no leaks). Then a check engine light came on for a "purge valve solenoid" fault. Got it cleared, later a check engine light for "torque converter clutch solenoid" came on, had it cleared. And finally a check engine light came on, but I didn't have access to a reader, so I just kept driving with it on, figured it was one of the above just reappearing.

At one point, started smelling gasoline fumes in the cabin, had to turn off air conditioner and keep windows open. At one stop for fuel, the gas cap was very difficult to open, like a suction was grabbing it.

Was getting horrible gas mileage, poor performance (obviously was running rich), and noticed when I "filled up", gas pump would stop like normal, but once I got rolling gauge showed I only was 7/8 full.

And then, about 300 miles away from home, after fueling, I started up and the engine check light was clear. I first thought maybe the bulb had burnt out, so I restarted and confirmed the light was indeed working.

It's been driving great ever since! Performance is much more like I was expecting for this heavy of a vehicle, and when not towing, I'm now getting over 20MPG. No "transmission faults", when in manual mode I can now see the gear number on the dash... It all of a sudden, just feels and performs the way I would expect the vehicle to behave.

So, summary, from the research I've done, and talking to my local mechanic, he thinks my EVAP was clogged. Either the hoses, or the air vapor canister was clogged / flooded, etc. And towing for long periods at 3.5K-4K RPM, the system finally unclogged itself. Running rich, poor gas mileage, the purge valve OBD code, the tank not getting full when refueling, etc. all point to that.

Thoughts?

 

I had a similar issue on a road trip to VA. Dusty roads/poor fuel for rural gas stops had my LR3 running like a pig. 12hr run out on the highway limping home, stopped to refuel, restarted and performance had returned. It was the beginning of misfire issues on one cylinder and ended up replacing the fuel injectors so you might want to have that in the back of your mind.

 

Just when i thought I was beginning to get the LR3 dialed in... walk out this morning and see an oil leak underneath. sigh...

 

I hear ya. Mine has been sooooo trouble free as of late. I am pretty preemptive with stuff. But I have this transfer box leak that I found, added leak stop which worked an ignored. Well it came back... new fluid, more leak stop and it barely drips. But its a leak and the only way to fix is to replace the darn transfer box... ugh... Gotta love these trucks!

 

The purge valve message obviously points to an Evap issue, not quite sure how this fixed it. I’ve had Evap issues before and they are pretty simple to fix when you know to look for it. It would seem unlikely that aggressive driving or towing fixed an Evap issue. I would still want to verify your Evap system is OK.

Your drive with a trailer probably resulted in an “Italian Tune-up”, where you basically run the engine for a long period of time at high rpm and it burns carbon and other junk out of the engine, namely the valves. I think it’s mostly an old mechanics tale, but there’s a lot of anecdotal evidence to support it. I’ve heard of at least one person intentionally doing this with a 4.4L LR3 and it improving things.

 

Well one huge issue that takes out EVAP is "topping" off the tank. Which should never be done with any modern vehicle. If done repeatedly, the EVAP system gets saturated with fuel including the carbon canister which in turn can cause some sludge/debris to get into the lines.