Missfire problem help please!!

[LiamETI]

Started yesterday was just at 5tho revs. now today its doing it all over rev range, its not constantly doin it just mainly when under load. iv changed the plugs it has ngk platanums in it but hasnt helped.
my mechanic friend thinks its the ht leads but would like other peoples opinions please

thanks alot

 

[Shifty.]

i had this ages ago and it was o2 sensors, apparantly there are two and if they are swapped it sorts it, had it done for free as i worked for renault at the time.

 

[LiamETI]

r they the sensors in the exhaust?

 

[Shifty.]

umm not sure exactly where they are or if the one in the cat is an o2 or lambda, someone else might know better about this, soz not much help.

 

[Cookson]

Check your injectors too

 

[hipwell]

The only lambda sensor which may affect fueling is in the manifold, the other is at the end of the cat but doesn't affect fueling it just reads what it sees.

Is it missing at Tickover? If so then disconnect each lead one by one And it should sound worse each time u remove one. If you remove one and the tone doesn't change then that's your faulty plug/lead.

But as said, a miss could be caused by many other things too

 

[LiamETI]

its not overfueling its just loosing spark. we took the leads off one by one yesterday but its not missin on idle its just when under load when drivin. any ideas??

 

[gti6steve]

Try a new set of leads then

 

[a1dan0204]

Mines missjng badly on idle any ideas on what to check first chaps? And what are the most conmon problems.

 

[a1dan0204]

Oh but it runs fine when driving, not a peep of a missfire.

 

[MicKPM]

Is there a slight hesitation when revving the engine from idle?

Mick

 

[a1dan0204]

Is there a slight hesitation when revving the engine from idle?

Mick

Yes i would say there is a slight hesitation when reving from idle, but if i apply a slight bit of revs and it runs at 1000rpm its completely fine.

 

[MicKPM]

H02 sensor/circuit is the most likely cause then IMO.

 

[Wakz]

Could be coilpack.
Mine was misfiring recently, when idle and when changing to second and third, mainly, seemed to get worse over a few days.

Had it shown to the mechanic and he recommended coilpack, mine had the coilpack and the leads connected together so the whole unit was changed and this resolved the problem running perfectly again!

 

[a1dan0204]

H02 sensor/circuit is the most likely cause then IMO.

Thanks, is that inlet side?

 

[franx]

Check your injectors too

similar prob with mine and was injector