Just by the way: when there was a relatively good weather (as for Scotland), I’ve took my MX5 to a silent spot with some long straight where are literally no cars, somewhere in Livingston, and done an acceleration test. Although not quite precise, it gave me some idea that the enine doesn’t seem to be struggling. She needs about 8.5s to get to 100kmh(63mph?), and if I’m not mistaken brand new one would do in 7.9s ??? It doesn’t sound bad for a 18 years old car.
When I followed that link Norton popped up saying it had blocked an intrusion attempt (from 95.216.176.198, if that helps). The warning would not go away until I did a restart.
JS
It would be a shame if MX5Nutz forum posts are causing an issue. Whilst an irregular visitor to their forum, I regularly pick up useful stuff from searches and along with Miata.net, a lot of our questions are answered by simply linking to one of their posts. If anyone is aware of a genuine threat from this activity, rather than error messages from over zealous anti virus software, please let us know. It would be a shame but the last thing I want to do when attaching links is to cause issue with malicious software.
To the OP - pleased to hear that the car appears to run fine with no issue other than apparent error codes and EM light. The VVT engine has a great reputation but there are areas where older VVTs generate odd error codes that defy the usual efforts and solutions. Quite a number have skirted the issues by using thinner oils, etc. Whilst this may appear to work it may compromise wear tolerance on the engine and is not addressing the real problem. A damaged or partially blocked VVT specific filter would make perfect sense.
I hope you are able to resolve this simply, perhaps by cleaning or replacing the filter outlined in the contentious Nutz link. Please report back when/if you find a solution.
Rob - I submit this thought, VVT on a long drive would show up earlier IMHO, - a short journey usually involves more gear changing and revs to negotiate immediate hold-ups, whie a longerd drive would normally mean less gear changes and lower revs. - Bearing in mind, others have suggested VVT becomes active above 3,500 rpm, and once in top gear you have to do more than 70 mph to get above 3,500 rpm. - My impression is that few drivers do this, preferring lower speeds. Also, on a long drive, engine oil becomes thinner, due to heat build up, so should present less problems for VVT to operate properly - again IMHO. On the contrary, heat via the exhaust will build up, which is why I opted for Robbies suggestion, it seems to indicate a cat sensor problem.
Granted my POV is limited, as I said earlier, I have no access to NBFL fault codes, other than the NB works manual I just gave away with the car sale, and that never covered VVT codes at all. - But never had an unrecognizable fault ether, except for ABS faults, which the MS309 does not read or allow. Despite more recent years of inactivity, I did some very long drives, like Notts to Beaulieu (2002 Spring rally) Durham (2006 spring rally, and down to zummerset, to Haynes (more than once) for the 2008 Spring rally. - Or several trips down to Brighton, each more than 150 miles. Not forgetting the hectic 600+ Km drive down to Ciron, in the center of France, and back again - in 2013 IIRC. All those trips are distinct memories in my mind, the car never missed a beat on any of them.
Still no EML since fault codes were erased. Btw. how could it be that MX5 has 50 liter tank, and yet when I hit “E” on gauge I can’t fuel more than 39 litres, even though I fill her litterally all way up to cap.
Common characteristic among MX5’s - don’t worry about it. Re-assurance lies within the fact that you have a good amount of fuel left, allowing you to pull into the next petrol station. Estimates will vary, but I found like you that I could never get more than 35 litres in, even if the gauge showed very low. (I’ve never filled up to the cap.)
With my NC I am confident in the 50 litre tank and the gauge and yellow light, however I once became quite twitchy after going fifty miles with the yellow showing, and then put 46 litres in.
Apparently the Check Engine light might also show if the fuel becomes very low - I assume because of air going through the pipes upsetting other sensors. I’ve not let it go so low.
Hi all. A quick update. Today, which is about 2 weeks since last EML light and codes being erased, I got P0011 code again. But no P0012 this time. EML appeared when cruising slowly. I’ve done over 300 miles until that. One thing I’ve noticed, was that when car was idling with EML on, engine revs were jumping between 500-900RPM and then after couple of seconds they stabilized. Everything else was normal, no change in engine behavior. I’ve cleared codes again, and I start to think that maybe I should change my oil, and see if it helps ?
Hi
Have a quick look at the last post on this from Miata.net.
https://forum.miata.net/vb/showthread.php?t=485252
It seems to mirror your symptoms and sounds like a relatively easy fix.
Good luck
Kevin
Now, I’m not getting P0011, but P0012, and completely no sign of anything going wrong beside EML. I got error reader in car in case anything happens, but when the weather will be better I may try cleaning this throttle valve thing which is mentioned in the another forum, as well as replacing oil with fully synthetic one.
Btw. does doing between 250-300 miles on a full tank sounds right ? I like to reev from time to time 
I’d carry out a hot, long drain oil change as a next course of action. A throttle valve fault wouldn’t cause a P0011 or P0012 DTC which are for the cam timing being over advanced or over retarded.