LR4 Restricted performance, rough idle

[Kris JM]

Hi All, my 2012 LR4 5.0L V8 started saying restricted performance 1/10 times we would start it. Local mechanic couldn’t figure it out and it would throw off codes. When this would happen, we would have 10% power, and all our systems seems to shut down (pics below).

Richmond, BC, Canada LR dealer found that it was the throttle body:

“The Rough Idle and SLuggish Acceleration is coming from a faulting Throttle Body. The Throttle Body is a valve that is timed by the Powertrain Control Module to open and close a valve to allow air to enter the spark plug chambers. When the Throttle Body Failes. it does not open at the correct time and it causes a misfire in your engine. You would need to rplace the Throttle Body to correct this issue $1649.00 plus tax including the diagnostic time.”

Hopefully when I get it back, it’ll be smooth sailing.

 

[HuskerBred]

I'm having the same issue, along with throttle body codes. I just cleaned the throttle body with MAF cleaner and it seems better. I'm wondering if replacing the throttle body fixed this for you.

 

[modesto_man]

Whoa! My 12 hse lux just did this for the first time last week... and did it twice. Would live to hear more from you or others on this!

 

[Red Top Engine]

Having similar issue, Cylinder # 1 missfire and restricted performance. I'm wondering if yours potentially has anything to do with the battery? These trucks are power hogs and batteries don't last.

 

[modesto_man]

Having similar issue, Cylinder # 1 missfire and restricted performance. I'm wondering if yours potentially has anything to do with the battery? These trucks are power hogs and batteries don't last.

I just replaced my battery a few weeks before it happened...

 

[Red Top Engine]

Have you obtained any of the codes? Please keep us posted as to what the results of replacing the throttle body are. Mine began to go into restricted performance mode on cold start up, cylinder 1 misfire. The check engine light would blink, then stay steady. I don't get the HDC and e-brake not available notice as you do. The only time I saw those codes where when it was power related, hence I enquired about the battery.

 

[HuskerBred]

Cleaning the throttle body seemed to fix the issue for me, until yesterday. All week it drove great, plenty of power, no lights or issues, then yesterday it suddenly dropped into restricted mode for a city block, I parked it and it started idling fine again. Then everything was fine the rest of the day. The codes I pulled were: P0106-00 (manifold absolute pressure/barometric sensor range performance) and P0101-00 (mas or volume air flow - circuit range/performance). Suggested fixes were mostly air intake system related. I just cleaned the MAF sensors and checked the filters, so hopefully that helps. This week I'll go down the list of other fixes and see if I find an easy fix before replacing components. And the battery is new and was recently on the trickle charger.

 

[Red Top Engine]

I've experienced similar fault with the MAF sensors, having to regularly clean them, progressively got worse and eventually replaced both.