182 Misfire?

[JToroPaz]

Got a bit of a strange intermittent issue. Day to day car runs fine, starts fine, doesnt idle high, revs fine and pulls fine. Then at motorway speeds it'll randomly loose power, slow to 50mph and sound like its either misfiring or being limited to 50mph. Similar sound to a pit limiter on a race car (see video)

Checked both spark plugs and injectors and both are fine, cam belt was replaced June 2021 (Ive owned it since November 2021). Work was done at a Honda dealer in Bradford not a Renault specialist, wouldnt really explain why its so intermittent but wondering if the timing is wrong.

I have gotten a check engine light yesterday after stopping off somewhere, then on start up the light was on.

What do you think, cambelt timing? Something else maybe ecu or sensor related? Trying to determine which way to go to solve it because its clearly not happy for some reason!

2004 Renault Clio 182 FF
117,000mi
Cam belt done June 2021
Other work in past 12 mo:
New water pump
radiator
alternator
K&N air filter
full decat scorpion exhaust
top and lower polybushed engine mounts

All work done before ownership, owned since Nov 2021


Video showing problem:

 

[Brigsy]

Get it scanned with can clip and read the fault codes stored. At a wild guess it might be a knackered injector

 

[Robbie Corbett]

Can't hear too much over the music.

I would think the injector would be present all the time, mine certainly was. I would suggest primary lambda but like Brigsy says its a very tough diagnosis without having codes read. Could be a lot of different things from lambda to throttle body.

Some of the cheaper code readers are very good now, might be worth picking one up and seeing what shows.

 

[JToroPaz]

Yeah it caught me so off guard I forgot to turn the music off before handing my phone to my mate to video it. I did wonder if it could be Lambda sensor related, it would make more sense than an injector. I checked the injectiors theyre clean, correct consistent resistance in all 4 and you can audibly hear them clicking away working with the engine running.

I'll get a scanner on it and see what shows up Ive been needing to get a new one anyway, I'll post some codes when I get them up

 

[Greeny.]

It is possible to have intermittant issues injector wise, one of my old cars had exactly that until the day it decided to completely fail.

 

[Robbie Corbett]

3 injectors wouldn't mean the car stopped accelerating, missing on all 4 would - if thats whats happening here in you vid?

 

[JToroPaz]

Yep it looses all power and slows to 50mph and holds there no matter how much throttle you give, then after a few seconds it will stop limiting it and it'll accelerate as normal. Hopefully the codes will shed some light on it, if its saying injectors I'll replace all 4. One thing I did consider actually, could the fact its been decatted be messing with the lambda sensor?

 

[Craigy69k]

First lambda sensor likely reading off or dead

 

[JToroPaz]

There we go, lambda sensor. I’ll replace it, clear the code and run the engine again and see if it comes back