I was driving home last night when I felt a slight jolt in the car, the check engine light starts flashing for about 3 seconds then goes to a solid light… Pulled over and done the usual visual checks and everything seemed ok so carried on with caution… Got back to mine and called the AA out today to run a diagnostics report to see what is causing it… Turns out it was an cylinder misfire.
I’ve only had the car a week, and the guy who owned it before me had the light come on once and took it to a Mazda garage where they kept it over night - however apparently they could not find anything wrong so just reset the fault? Could this have been the same thing?
My main concern if this has happened before is will this have any effect on the rest of the car? Will the cat be effected with the occasional unburnt fuel?
It’s only happened to me once, but I’ve had the car less than a week!
The spark plugs were changed Dec 2013. Not sure about HT leads… could it possibly be to do with the coil pack?
Do you know if the code was for a random misfire or was it cylinder specific? Could be coil packs or HT leads. Or a whole host of other things in theory. a flashing engine light does mean that catalyst damage may occur but if it’s turns to a steady one then the fault has cleared. Intermittent misfires can be hard to diagnose.
Thanks for the reply. I’m not sure exactly what the fault was, just the AA man run the test and said it was a cylinder misfire… the fault has been cleared now. Tempted to get my own kit so I can see exactly what the code is if it happens again!
Is it okay to continue driving knowing this has happened? Should I replace spark plugs, HT leads and give the MAF sensor a clean?
I love the car, just seeing these warning lights coming up within a week of owning is concerning me a bit!
If the light is not on I wouldn’t worry about driving it. You did the right thing by stopping when it did come on though.
it’s certainly worth changing the leads, plugs and cleaning the MAF hot wire for piece of mind if that suits you. I’d suspect a coil pack issue if I’m honest but they are expensive so I wouldn’t change those on a whim just yet.
Ah the coil pack… That was a slight suspicion of mine too however, I thought the car would idle at high revs/not drive so well when this needed doing… I guess if I do all the cheaper jobs first I can rule them out thanks for your help!
Did they give you any error codes when the car was checked.
Coil units on both the 1.6 and 1.8 cars are the same, so can be interchanged. If the error code occurs on fixed cylinders, the coil units can be checked by swapping over to see if the error moves to another cylinder. They look after 1&4 and 2&3.
Sophie, getting your own diagnostic reader is a good idea. I bought one of these cheap generic diagnostic tools (own-badged by various distributors) and it seems to work well enough on each of the cars I’ve tried it on, the only problem I had was that its plug was very stiff when trying to push it onto the MX5 socket.
There are various sources of the DTC tables of fault codes available on-line in the usual Owners Clubs; last year I was able to find those for my NC and the old Vectra, and also a friend’s Focus and Mondeo. I noticed that most of the codes are the same across the different makes and models, and it is only as you get down towards the ends of the tables that the model-specific differences appear.
There is a very good explanation of most of the standard DTC codes and Detection Logic on the Samarins website with lots of real examples on different cars and possible causes and cures, but it is a bit too much to print out
If I can find the original sources again for the much more compact printable tables specific to the MX5s I’ll edit this post to add the links to them.
And I think Robbie is right when he suggests checking the leads and plugs first; it is common for a bad connection to be temporarily improved by a bit of wiggling the wires etc about, but it will return.
Your car will be VVT type engine so my advise is to change the leads and plugs and see if it improves or after that coils, 1.6 and 1.8 in your model are not the same as VVT 1.8 has coils on cam cover as above
Definitely have a look at the Samarins website I mentioned above. It goes into detail on all the possible causes and cures for multiple cylinder misfire, and is far better explained there than I could do here. Look at the paragraph for code P0300.
Would you say stick to Mazda parts only? I’m pretty sure it’s going to be the coil packs so just pricing up… They do a Mazda genuine and aftermarket part on mx5 parts… Anyone had any experiences with an aftermarket coil pack?
