'99 micra runs lumpy in hot weather

[johnlindsay]

I can travel start stop traffic for half an hour or so with no problems but if I return to the car after a period of time and try again it will run lumpy.

motorway driving will intermittantly make it run lumpy.

The worst it gets is when it has been sitting in the sun and I use it. No problems with starting but very quickly it will run lumpy almost to the point of stalling, with a smell of fuel.

My mechanic says theres no codes when he tests it although he has replaced the alternator which was charging low. He also thinks there was a problem with contacts on a plug under the air filter (this plug is slighlty melted, could this be the cause of my problm ??)

Please help

[navysnail]

depands on what plug it is. i would say to check your CTS (coolant temp sensor) if you have one, i dont know much about micra's since we dont have them here. a "lumpy" runing usualy indicates a problem with either A/F ratio or your timing.