- My model of MX-5 is: 2005 NC Sport 2 litre. Has done 51000 miles.
- I’m based near: Cirencester
- I’m looking for technical help or recommendations on: The engine “hunts” (slight misfire) at about 1800rpm constant throttle. Higher or lower revs are fine and it accelerates away no problem. Also there is what I will call a flat spot when you pull away i.e. the engine dies if you pull away gently and if you dont catch it it stalls. Car has just been serviced and plugs have been replaced but the issues are still there!! Any suggestions greatfully received, Thanks.
I don’t know about the hunting, there could be several reasons, but all unlikely with an NC. Speculation is fruitless, it needs a good hands-on look.
But flat spots, that’s another matter. When I bought my NC it had a bad flat-spot at low revs, and with the clutch being near the floor it was difficult not to stall when moving off from rest.
However when I refilled with V-Power the flat-spot went away.
And several months later a ten minute (but only when you know how) adjustment fixed the clutch pedal.
You might find the V-Power also fixes the hunting, but fuel is just one of several possibilities…
I saw a video about that problem on another car (non-MX-5) recently, I can’t remember the exact video (too much video watching of late) but it was either the Mass Air Flow sensor needed cleaning, or the fuel injectors needed cleaning, both of which are said to cause those issues you describe as I understand it.
In one of the videos using V-Power like fuels was mentioned because of the cleaning agents among other things in it.
By yourself? Reason I query that is, again not related to an MX-5, but my Dad had a Citroen which on holiday developed an issue with the brakes (gentle press = full brake power and much occupant discomfort).
It went to the nearest official dealer, and they plugged it into the official computer system they use. Once all work was done we went for fuel, then while at some lights the car suddenly started revving from idle rpm to max and back to idle. We went straight back to be told they’d noticed this happening but figured we must know about it 
A second go with their diagnostic system and the car was back to how it had been before it went on their system in the first place.
So basically, was it at a dealer service and could they have messed up a setting on the car to cause this?
Thanks for all the replies gents. I always run it on V Power and the service was carried out by an “old school” proper mechanic (not a main dealer “vehicle technician”) I have used for years on all my cars. Dirty or faulty MAF is a good shout. Will pursue that to start with.
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