Hit and miss - misfire

[Clingoo172]

When started from stone cold, runs fine, revs clean with no flat spots, but as the engine gradually starts to warm the engine develops a misfire that's not exactly consistent but scattered so to speak, the car will run albeit pretty roughly but it can momentarily clear with some revs but there's no ryme or reason to it if that makes sense ..?
New injectors & correct plugs recently fitted, also single lambda on my Ph1.
Any thoughts on this and has anyone experienced this strange fault before with no current fault codes showing...??

 

[Amos91]

Does it get up to temperature okay? Thinking a possible issue with the coolant temp sensor.

 

[Clingoo172]

Yeah it gets up to temp ok, seems to be as it warms the problem is only accentuated. Starting it from cold with that disconnected makes no difference too
Real puzzled, looks to be a new crank sensor so doubt that is the culprit as its unlikely it would run at all if that was at fault as its dry and clean around that area too so not effected by any oil leak

 

[VR46-G@Z]

MAP/MAF sensor maybe? This happened on my Alfa V6, I know a different car but it ran fine until it got up to temp then stuttered like a good un... sounds an air/fuel sort of issue...

 

[loggyboy]

Check the white connector block under the fuse box, it caused issues on mine and turned out to be corroded connectors giving an unstable connection.

 

[Clingoo172]

Thanks for the suggestions guys, never gave those any thought and yet i have had similar issues on other cars behaving along the same lines. Will check and report back :wink:

 

[Clingoo172]

Ok, state of play at the moment, changed leads, plugs, coilpack, with known good ones of a mates car that has no issues whatsoever. Checked the timing by inseting the genuine Renault tools, all bob on, code read again with no faults coming up but still have this persistent misfire. Also checked the big white connector plug as suggested, all clean with no corrosion. Don't know where to go from here now, any advise would be gladly appreciated as, ive heard that Ph1's can be prone to this fault so if there's anyone out there that has experienced this, please could somebody give me a little shove in the right direction ....?

 

[loggyboy]

Did you use proper NGK PFR6E-10 plugs?

 

[Clingoo172]

Did you use proper NGK PFR6E-10 plugs?

Yep, brand new.
The car was running well earlier, no more then five minutes after setting off in it, it started playing up again....?
The leads are in the correct orientation too, and thats not relying on thr incorrecly marked leads that can catch most peole out...

 

[Clingoo172]

Well i cleaned up the MAP sensor of excess oil build up with panel wipe solvent and found a small amount of water kicking around the leads so not sure what has made the greatest difference but combined, has made ALL the difference !!! Runs sweet now and healthier than ever and treated it to some good oil as bore wash had deffo thinned the oil down and pissed out like water upon dropping it out...:fearful:

P.S.

Happy new year peeps !! :stig: