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I have been experiencing erratic running - when I accelerate, my 1986 Hi line fuel-injected (all original and driven every day in the country) hesitates, almost to the point of failing altogether. It doesn't always happen - just once in a while. I'm happy just cruising along at 'fifty mph with both hands on the wheel' (as my imperious old aunt would insist I do), but if I put my foot down ...know what I mean?
My mechanic (and I am fortunate it would seem to have found someone who is happy to work on RRs at all) suggests problems with the air flow metre. Might this well be the case and can I fix it? Recent work on fuel system relays, plugs, hi-tension leads, etc. means the car is at least now running again, but that old acceleration problem is yet to be solved.
 

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1989 Range Rover Classic
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It could be a few things, I assume you have the flapper type air flow meter rather than the hotwire MAF?
 

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It's worth looking into the TPS "throttle position sensor " which is located on the end of the throttle butterfly plate.

It's essentially a multi track variable resistor that reports both steady state position via voltage gradient to the ECU so that it knows how far the throttle plate is open.

But the symptoms you've indicated relate to the secondary function, specifically it gives a read of how fast you move the pedal and determines from that rate of change how much fuelling to add over and above steady state demand. In other words it facilitates an accelerator pump type strategy that makes it go when you ask it.

So flat/gentle running is mainly mapped to give correct mixture and economy, additional to stoke the fires is over and above this level and they feel quite lethargic without the additional fuelling on demand.

The TPS is one of those items that's getting difficult to scource from original manufacturer, there's good alternatives but they aren't cheap.

There's test routines to determine if the TPS is compromised, mainly it has to change in continuous linear fashion with no big jumps or gaps. I'd test this component first as prime suspect to verify yes or no before chasing elsewhere.
 

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I have been experiencing erratic running - when I accelerate, my 1986 Hi line fuel-injected (all original and driven every day in the country) hesitates, almost to the point of failing altogether. It doesn't always happen - just once in a while. I'm happy just cruising along at 'fifty mph with both hands on the wheel' (as my imperious old aunt would insist I do), but if I put my foot down ...know what I mean?
My mechanic (and I am fortunate it would seem to have found someone who is happy to work on RRs at all) suggests problems with the air flow metre. Might this well be the case and can I fix it? Recent work on fuel system relays, plugs, hi-tension leads, etc. means the car is at least now running again, but that old acceleration problem is yet to be solved.
As this system is very basic it is better to check items via substitution. Do you know anyone that has a similar vehicle that you could use to test items?

I would suspect the ECU for this issue. There is a very good site in the UK that describes faults with this item, Carelect .com. Unfortunately Range Rover Classic parts are quite expensive outside the UK. Jaguars of the same year use the same air flow meter if that helps.
 
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