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Mis fire

Hello everyone. My mrs has a 2003 micra 1.0e had it for a good while. Last year it got stood up for for about 6 months. Anyway a new battery fitted started easerly run for a while then started mis firing... so changed coil packs new plugs started lovely... took car out started a slight misfire and totally died. So got it home and changed injectors worked for about half hour and back to square one wont even start.... so out with fuel pump cleaned it and sounds like it's working.... car started again hoped that was cure but no... same symptoms fire then died. J have a snap on computer and it says misfire cylinder 4 then mis fire all cylinders... oh and I filled car with fresh fuel. So yesterday I changed the whole air box off a running car and car run great... for about an hour and died .... left car for 20 mins waiting for AA... and tried my luck. It started with a mis fire managed to get it running on 3 cylinders and got car moving held idle at 3000rpm and made my way home and nearly home car runs fine.... what is going on ??? Someone please help what else can I change? Manh thanks steve
When in breakdown fault mode, measure fuel pressure before the regulator & after it at the injectors supply.
If supply pressure is low, change the fuel filter.

The K12 is notorious for obscure electrical faults, including failed ignition switches, relays, corroded or cracked fuses, fuse block base receptacle contacts failure, and the wire terminations under the fuse block bases! This is mostly due to poor quality termination connections and moisture ingress in and under the fuse base blocks in the engine bay.

These faults often present as intermittent faults, as the loose or corroded connections heat up & become high resistance joints/connections that cool down on failure only to resume operating after a half hour or so as you describe.

Test, inspect & test again before replacing parts at random.


To trace and resolve these issues requires a circuit diagram, a multimeter, and basic electrical fault finding/repair knowledge.

Good luck