Not the usual misfire

[Bbrooks]

I've been chasing a misifre for a while now. It is not the injectors as far as i can tell (they are brand new, has cured a different issue) and the lambda is new (had rough idle). The plugs, leads and coil pack have been replaced in the last 6 months.
It has also hand a new (second hand) throttle body which cured an issue with it cutting out at large throttle openings.

The problem I now have is if I give it a lot of throttle below 4k rpm the car violently judders as if the injectors / TB is being turned off and on quickly, it is worse lower in the rev range and does not happen at all above 4k rpm.

I probably need to take it to a specialist (know of anyone in kent?) but thought it would be worth asking here first.

Cheers.

 

[Pistachio]

Mine is doing the same recently. If I only give it a little throttle, it is fine. Any more and it is like it drops 2 cylinders. But higher revs are ok. If I am thrashing it at speed it is almost normal, but I still can't give it 100% throttle.

A few months ago I replaced all the injectors which cured its problems and was fine up until recently.

 

[Bbrooks]

Well the alternator has just gone today so I'm hoping that once it's fixed it sorts it out.

 

[Pistachio]

Have you had a code reader on it?

 

[Bbrooks]

Have you had a code reader on it?

Yep, it isn't throwing any codes at all.
I don't get any warning lights, just the misfire.

 

[James363]

I had the very same thing happen, changed coil, did nothing, changed the leads to magnecor and it fixed it. What brand are your plugs, leads and coil? I would recommend NGK for the plugs and coil, and magnecor or renault genuine for the leads.

 

[Bbrooks]

I had the very same thing happen, changed coil, did nothing, changed the leads to magnecor and it fixed it. What brand are your plugs, leads and coil? I would recommend NGK for the plugs and coil, and magnecor or renault genuine for the leads.

I've got the proper NGK plugs, HAAS coilpack and ECP leads.
I'll get some Renault ones and see if this helps.

 

[James363]

Yeah, if it wasn't a ballache to get the leads out I'd offer you to come over and try the magnecor's aha... It would sound like the ECP leads, I think the way they heat up in the Clio between the rocker cover and plenum causes the cheaper leads' insulation to break down faster than the same material would in another car. That's only speculation though.

 

[dan112]

I had the same sort of misfire on my cup which also had ecp leads fitted, when I removed them from the plugs the end of the leads were totally rusty, the leads had obviously letting water past them and down into the plug wells. I replaced them with a used set of genuine Renault leads and it's been perfect ever since.

 

[bloke]

bin the leads, seen them give running problems from new.