REDUCED ENGINE PERFORMANCE!!!!!!

I HAVE JUST REBUILT THE FRONT OF MY S/C 4.2 2008,EVERYTHING IS FINE UNTIL I GIVE IT SOME THEN THIS MESSAGE APPEARS AND THE CAR GOES INTO LIMP MODE????? I THEN GO TO GARAGE COMPUTER SAYS NO FAULTS , THEN I DRIVE NORMALLY NO PROBLEM,BUT AS SOON AS I GIVE IT SOME MESSAGE APPEARS REDUCED ENGINE PERFORMANCE !!!!!!! ANY IDEAS ,ANY SUGGESTIONS

WHAT DID YOU DO TO THE FRONT WHEN YOU REBUILT IT? WHY DID YOU REBUILD IT?  Gone - 2008 Stornoway Grey RRS 2.7 TDV6
Gone - 2009 Buckingham Blue RRS 2.7 TDV6
Gone - 2010 Alaska White RRS 5.0 V8 Aspirated
Gone - 2017 Chawton White RRS 5.0 V8 Supercharged
Current - 2010 Java Black RRS 5.0 V8 Aspirated
Current- 2024 RRS P400 SE Dynamic

I HAD TO FIT A NEW WING ,BONNET AND HEADLIGHT,ALSO RAD PACK HAD A LOW SPEED SHUNT ,NO STRUCTUAL DAMAGE, THIS IS ALL CAR HAS NO FAULTS ON DASH ,OR COMPUTER ????

I'd suggest the ECU needs looking at - maybe replacing or reflashing. It might not be obvious to the eye, but maybe the ECU got damaged in the impact. Everytime you give it some beans, the ECU spuriously sees a failure event and goes into limp home mode.... this "garage" you've taken it to, is it a LR dealer?

PS: no need for CAPS, we don't need to be SHOUTED AT!  

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hi m8

the garage is not a L/R and has only a bosch hand held computer,i live here with my wife im originally from london i am mechanic minded and understand what your saying, but i agree that the fault would be etected on a genuine L/R computer/diagnosis machine,i was thinking about the air intake and the control valve/compressor which pushses air into the engine???

Realistiically, it could be any number of things but best to get it into a LR shop (or at least an LR indy if you can find one) but not sure if you'd have to travel miles to find one in CZ? 

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Do a search on here, for "Reduced Engine Performance" - it is a well known issue with the supercharged 4.2 and there is an easy fix. I think it's to do with the fuel pump, but don't remember.

THANKS ALL !!!!!!!



ALL SORTED NOW GOES LIKE SCALDED CAT !!!!!!!!!!!!!!

Hi mate wat was ur issue with the car and how u fixed it as mine keeps going on reduce proformance and won’t rev past 3k revs and has missfire thanks

And can u hear hissing noise on ur engine near the pcv valve as I’m new to these and sounds like a leak but if u presss on top of the circle pcv valve it stops hissing

I would have thought it was the Aux suoercharger pump being wired the wrong way as its a known fault with them i changed mine for the same reason

I’ve got recipts for it being changed at landrover on mine so not sure if will be that would the pump cause missfire thow it said on recipt changed wires and fitted new pump

if yours has had it changed then it will not be that you got any codes shauny from it

Just misfires 2468 I think was the person who I bought it off cheap said it ran out fuel on its mot and ever since that it not ran properly when ur driving it it won’t really go over 3k revs so u aft to put ur foot slightly on the pedal and u can achieve up to 50mph but u can feel the car like bucking we’re its like pulling back forth like it wants go but being held back also some days u can put ur foot down abit off the start and gets up to 40 straight away but then will do same again and u get engine light flash it’s thow it’s like running out fuel feeling I’ve changed spark plugs weekend had it terraclean weekend changed coil pack on 1 of them as it’s been changed before so fort might been dud 1 I’ve just orderd pcv valve as it’s hissingg and if u push down on the circle valve on the plastic it stops so dunno if that leaking So fort I’ll try that but part not come yet I was thinking of changing the fuel pump and filter next incase the fuel pump is faulty or fuel filter blocked in tank

Get someone with an IDD tool to get codes or nanocom if we have codes it is a bit easier to help you it could be an air leak but does sound a bit more like a fuel issue but without codes you will be changing things maybe when they don’t need to be done