engine light at 80mph 172 cup

[sinner]

hey people new to the forum and only got the car on tuesday

as title says my engine management light came on bout thurs so took it for diagnostic which came up with errors

fan speed 2
missfire causing cat damage intermittent

cleared the fault started ran tested again no fault

so yesterday seen as the car had been stood by previous owner since feb , i changed the oil and filter took the spark plugs out an wire brushed any deposits off as apparently it had new leads plugs an coil pack bout 6 month ago

took her out all was fine

cruising today but when it reaches 80mph in 5th engine management light starts flashing

any ideas where to go from here as im totally new to renaults used to own vws

thanks in advance

 

[Fred@BTM]

what plugs does it have?

 

[MicKPM]

The flashing MIL means you have a level 2 fault... not a perm fault but one that can damage the life of the CAT.

Most probably due to a missfire so the usual culprits to suspect; HO2, CTS, ATS, Plugs, Coil

 

[sinner]

thanks for the replys there ngk plugs in it,

yes mick the diagnostic came up with a intermittent missfire im just stumped to what it might be as it only seems to miss at top revs car seems to be running fine temp on display bang on half way getting good mpg its had new coil pack new leads just serviced

no lambda fault came up on diagnostic when the light was perm on just missfire was logged and fan speed 2

 

[sinner]

well cars been running fine since i changed the plugs an put some slick 50 through it then today on motorway put foot down an it flashed a lil an then went an didnt come back feels a bit hesitant like its not at full power then othertimes its fine any ideas guys

mpg is fine temp on display bang on half way could it be an air flow sensor?? ive just noticed sum1 has drilled the bottom of the air box aswell :S