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2010-2012 Range Rover MkIII / L322
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Discussion Starter #1
I purchased my first Range Rover, a 2010 full size HSE.
Love the truck but one this is bugging me big time.

When driving on the freeway and I reach about 1800-2200 RPM's there's a surging in the RPM's.
So strange. It is fine up to and even after, but then I'm going upwards of 75 mph.

Not sure if it's more pronounced in cruise control or trying to maintain a constant speed with my foot.

I looked around the forum, saw some similar posts, but no fix to this issue.

Anyone have a fix for this issue?

I'd appreciate any help with the irritating issue.

Thanks,
Rich
 

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2010-2012 Range Rover MkIII / L322
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Discussion Starter #2
Interesting.....102 views but no replies.
Some research did connect with a few similar results.
Appears either the fuel or transmission torgque converter.
Anyone else have this issue?
Rich
 

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Interesting.....102 views but no replies.
Really? Perhaps no one has had this issue. Perhaps they have had it not really noticed it. Perhaps they noticed, but chose not to do anything about it. Then there are the folks that decided to do something about it and maybe haven't seen your post yet.

Just because someone has viewed your post does not mean they have experienced the same issue. In fact I really can not think of anyone having a surge issue that stands out. It certainly is not a more common or reported issue like the timing chain guide issue rearing it's head lately. Any way, I know it;s been a week, but with only 102 view in 7 days on a busy site I wouldn;t sweat too much.

As there are far more fuel possibilities I would lean towards fuel filter service or pump getting weak. Possibly dirty injectors not able to balance that particular fuel load? If it were surging at idle or at stop lights I would suggest an intake cleaning.
 

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Not sure if this is your issue but mine was behaving similarly and assumed the intake needed cleaning. Was on the list with no sense of urgency. Car died recently (I posted about this) clogged fuel filter. Once replaced no more surging issues, no more idle/power issues. One of my previous rigs had torque converter issues, it was most prevalent going up hill @ 20-30mph... Surging and drone.
 

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2010-2012 Range Rover MkIII / L322
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If you're able to check a couple of small things under the hood [for free] you may be able eliminate some possibilities.

Open the hood and you'll see a flat cover above the center area of the engine.

Lift up the front edge (it's located by two rubber female cups under the cover pressed onto plastic male ball mounts attached to the plastic inlet manifold). Once the front edge is up a couple of inches or so, pull the cover towards you to release the two slide in mounts at the rear.

Either side of the radiator, behind the headlamps, are a couple of rectangular boxes which are the air filter casings. There is a five pin electric connector connected to a sensor on the inner corner each of these air filter casing's lids.
Check to make sure that those connectors are tight on their sensors. Pull lightly on the wire to the plug and see if it detaches fairly easily (it shouldn't).

The sensor's plastic becomes brittle over time and although they can "appear" to be connected, occasionally the sensors attachment point is broken during air filter replacement and although the plug will push together, it will actually be loose enough to throw a fault code during certain rpm ranges (may or may not turn the CEL on but will be logged in the fault memory if so).

If you're not sure that the air filters are fairly new, you may want to check those for cleanliness. If you discover K & N filters within your air cleaner, change them back to the OEM style.

You check the filters by removing several phillips-type screws which hold the two halves of the air cleaner box together. You'll also have to undo the large air hose clip and push the large hose aside (towards the center) to give you room to lift up and pull the upper half of the airbox aside, AFTER pressing on the tab and disconnecting the aforementioned sensor's plug. You can also remove the sensors from the upper half by removing their two mounting screws and withdrawing them from the lid(s) with the wires still attached.

Check to make sure that the air hose to the center manifold throttle body area is fully seated and that the large hose clip is tight.

Towards the driver side, on the back side of the plastic air intake which connects both air filters to the throttle body, there's an inch or so diameter hose which runs from the left side cylinder bank area (the two thinner plastic pipes nearby are fuel pipes) about 2/3rds of the way between you and the back of the motor, which snaps into the back of that housing. The hose is disconnected by squeezing the sides of the connector together and pulling towards the rear.

Make sure that that hose connector is fully seated too. If you're not sure, squeeze the sides of the connector together, pull backwards to detach then reseat it, making sure you're happy it's now locked in situ.

While you're in that vicinity, make sure that the engine oil filler cap is tight, too.

If all that easy stuff is OK, and you've found nothing of consequence, you may want to try adding a fuel system cleaner to a couple of tanks of gas to see whether that helps, in the next few hundred miles.

From that point forward, the least expensive way to source the cause of your problem is to pony up an hour's labor at the local dealer and have a diagnostic test which will pull all the codes logged.

Although folks often complain about dealers (and I understand why) the later Range Rovers are pretty reliable and the data logging on them consistently provides enough info to more accurately diagnose problems such as yours. Once you have the diagnosis, you can decide on how to correct the issue.

It could be a high pressure fuel pump (two engine driven pumps located under the right engine mount area), it could be the fuel control module (under the right rear seat), it could be a low pressure sensor (under the driver side wheel liner), it could be a wiring issue (many have experienced unknown rodent damage to the wiring harnesses) etc etc. If you lived locally I'd lend you my diagnostic kit but I see you're in CA.

If you're not comfortable looking under the hood yourself, better to take it to the dealer. You'll save in the long run, rather than simply throwing parts at your car in the hope that you hit the jackpot with a lucky guess, absent attachment to an LR diagnostic tester.

Rob
 

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2010-2012 Range Rover MkIII / L322
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Discussion Starter #7
Rob,

Thank you very much for the thoughtful and very detailed descriptions!!
This is exactly the kind of assistance that makes these forums so great.
I'll give this info to my mechanic and have him check it out.

Any chance it could be the torque converter?
Rebuild or replacement is a fair size job and may cost around $2,000-$2,500.

I will check the things you've suggested in your reply first before going the torque converter route.

Kind regards,

Rich
 
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