Misfire Occasionally

[cardi]

My 1.2L has been perfect for years but in the last few weeks has taken to the occasional 'hiccup' misfire, worse when cold but can happen anytime, also underpowered when cold. I suspect fuel rather than ignition but you know how hard it is to pinpoint as it is intermittent. I notice that there is an inward hiss when I open the fuel cap so tank vent must be blocked. I could just wait for it to finally fail or clean the componants one by one but has anyone had this experience?

 

[paul_k10_Lx]

fuel filter maybe??

 

[sketch]

Fuel filter - clean/new spark plugs - check/new HT leads - check/new rotor arm - check/new dizzy cap - basically check poss replace with new, the fundementals of spark and fuel.

 

[mankian]

sorry i cant really help you with the misfire coz i would only be quoting sketch lol and im still trying to solve a similar problem myself... but my car(K11) also hisses when i open the feul filler (like theres abit of a vacuum in there) - that bad? coz i fort it was normal...

 

[cardi]

Mine didn't hiss before and in the manual there is shown to be a vent so no vacuum should be there, shouldn't cause misfire though. I have started one by one testing. Have checked plugs, air filter, fuel filter amd lift pump. Wll move on to cleaning carb soon. Not much I can do with elect. ignition.

 

[SammoHung]

Do you mean MISSFIRE(nothing!) or BACKFIRE (bang!)?

cheers,

 

[cardi]

It is a misfire. You get the occasional jump at anytime but more often just after cornering or when climbing. There are so many minor valves and switches with a converter and fully electronic ignition. I could go to a Nissan dealer and have the system analysed on their machine but it will cost. I wil keep running it and hope more clues emerge, need Sherlock Holmes.