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FOUNDING MEMBER
1995-2002 Range Rover P38A
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484 Posts
Discussion Starter #1
My Rangie has started making odd changes between 2nd & 3rd gears. On light/medium acceleration it seems to change into 3rd, immediately change its mind and change back to 2nd, before then, a few moments and a bit more speed later change up to 3rd again and carry on as normal. I thought at first it was a flat spot on acceleration as that is what it feels like but the revs drop as it changes up to 3rd then back up as it drops back into 2nd. Any ideas what might be the problem?
 

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FOUNDING MEMBER
1995-2002 Range Rover P38A
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484 Posts
Discussion Starter #3
Not checked fluid level - although it was replaced last summer! Is this a symptom of low fluid level?
 

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541 Posts
The RPM dropping when going up to 3rd or increasing when dumping to 2nd is not out of the ordinary, although I can't really even feel those shifts in my SE so you may want to start as suggested by examining your fluid level and examine the color as well.

Does "Sport" mode provide the same results?

You may need to just be a little more firm with the skinny pedal.
 

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FOUNDING MEMBER
1995-2002 Range Rover P38A
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484 Posts
Discussion Starter #6
Fluid level is fine. Fluid colour is fine ......... as expected as it was only changed last summer! Has been behaving itself impeccably since I reported the behaviour here :think: . I am suspecting the controller or some sort of pressure switch playing up - does anyone know how the controller measures the torque in order to request a change?
 

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FOUNDING MEMBER
1995-2002 Range Rover P38A
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484 Posts
Discussion Starter #7
Update. Symptoms got worse and began to feel more like a flat spot rather than a gearbox problem and eventually it threw two fault codes - P0171 & P0174 so running lean on both banks. Cleared the codes but they reappeared pretty quickly so replaced the NGK spark plugs with a brand new set of Champions and also removed the MAF for a good clean. No more flat spot and it's now running really well but it is throwing a P0102 fault code now - MAF circuit low input. Is this an adaptive setting that will correct itself or is the MAF on its way out?
 

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Premium Member
2010-2012 Range Rover MkIII / L322
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4,635 Posts
Odd gearbox behaviour can come from a failing MAF, and the codes you've just read show the MAF clearly not working as it should. My guess is that you've purchased an aftermarket unit which has been on for 6 months. Correct? :think:
 

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1995-2002 Range Rover P38A
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484 Posts
Discussion Starter #9
Rich998a said:
Odd gearbox behaviour can come from a failing MAF, and the codes you've just read show the MAF clearly not working as it should. My guess is that you've purchased an aftermarket unit which has been on for 6 months. Correct? :think:
No, it's the orginal item - been on for over 9 years. Prior to cleaning there was no specific MAF fault code flagged just the two codes showing lean runing on both banks. Since cleaning the MAF, no lean running codes just the MAF low input - but it's not flagging it all the time - it's intermittent.
 

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FOUNDING MEMBER
1995-2002 Range Rover P38A
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484 Posts
Discussion Starter #10
Re: Odd Gearbox Behaviour Changing 2nd to 3rd ***Now Solved***

Well the P0102 fault code finally arrived to stay and flat spot returned with a vengence - at around 2600 rpm, whilst under light acceleration, the engine would hunt with revs dropping back to 2400 then rising to 2600 and repeating over and over until a bit more throttle was applied and it could be driven through - I had confused this engine 'flat spot' behaviour with the gearbox trying to change gear ............... turns out to be nothing to do with the gearbox.

Despite dire warnings on this forum about after market MAF sensors I tracked down a reasonably priced (~£80) Lucas replacement MAF sensor for the OEM Bosch unit. Rangie now back to rude health - no more flat spots and completely fault code free after extensive testing.

I can only assume that the OEM MAF sensor was on its last legs and beginning to fail which resulted in the original 'flat spot' behaviour and lean running codes. Cleaning it finally finished it off completely!
 
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