Low RPM misfire

[Patrick Bateman]

My code reader has identified a misfire on cylinder 3 but curious if the symptoms here can point towards anything in particular before I take it to a garage-

• Revs with no issue when in neutral only (no load)
• Obviously misfires when trying to accelerate in any gear at low revs- happens from cold and once up to temperature
• Once above approx. 3000 RPM there is no obvious misfire and the car accelerates as normal in any gear. Can rev all the way to the limiter with no issue.

Any likely culprits with those particular symptoms?

 

[WelshViking]

My code reader has identified a misfire on cylinder 3 but curious if the symptoms here can point towards anything in particular before I take it to a garage-

• Revs with no issue when in neutral only (no load)
• Obviously misfires when trying to accelerate in any gear at low revs- happens from cold and once up to temperature
• Once above approx. 3000 RPM there is no obvious misfire and the car accelerates as normal in any gear. Can rev all the way to the limiter with no issue.

Any likely culprits with those particular symptoms?

Did you find the cause as I have exact same problem ....changed spark plugs but still have issue . Cheers . 🙂

 

[Sir Nancy Flowers]

Its more than likely to be one of a few different things:

Coil pack
Spark Plugs
Injectors (In my experience this is the most likely)

Failing that, its off for a leak down test.

This is assuming you have a 172/182? The reason the OP didnt get a reply was probably because we havent been given enough information: Make (Renault I assume), Model, Engine etc etc etc.

Also, a code reader wouldnt go a miss. Otherwise youve effectively walked into the doctors and said 'I hurt' in terms of diagnostics.

 

[WelshViking]

Its more than likely to be one of a few different things:

Coil pack
Spark Plugs
Injectors (In my experience this is the most likely)

Failing that, its off for a leak down test.

This is assuming you have a 172/182? The reason the OP didnt get a reply was probably because we havent been given enough information: Make (Renault I assume), Model, Engine etc etc etc.

Also, a code reader wouldnt go a miss. Otherwise youve effectively walked into the doctors and said 'I hurt' in terms of diagnostics.

I have a 2013 Clio 1.2 petrol.
Haven't as yet got a code reader but plan to this weekend.

 

[Sir Nancy Flowers]

I have a 2013 Clio 1.2 petrol.
Haven't as yet got a code reader but plan to this weekend.

Good stuff.

A code reader will get you much much further as it should help indicate where the fault lies. In your case, you should find its either the injectors or coil pack thats gone as you have checked sparkplugs (just check theyre the correct type!)

 

[WelshViking]

Good stuff.

A code reader will get you much much further as it should help indicate where the fault lies. In your case, you should find its either the injectors or coil pack thats gone as you have checked sparkplugs (just check theyre the correct type!)

If it was the injectors, would they work ok for 1st 20-30 mins ? Same with the coil pack... Would it not be faulty on start-up as well ? Thanks for your help, by the way .. just been watching how to remove and test coil pack, and how to clean throttle body. 😁

 

[Robbie Corbett]

Ignition coils can get worse as they get hot. So start out ok and 30mins later you get a miss. I had a BMW which did exactly that years ago. Eventually the coil just failed and the missfire was there all the time which made it much easier to identify which coil was bad!

 

[Patrick Bateman]

Thought I updated this.

Not sure there was an obvious answer in the end but I ended up replacing the spark plugs, ignition leads and coil pack and it was (eventually) sorted.

I say eventually as a new misfire immediately appeared after this which, after many hours of fault finding to no avail at the original garage then getting the car transported all the way to SWR in Stirling, turned out to be a nick/damage to one of the new ignition leads they hadn't noticed.

 

[Sir Nancy Flowers]

If it was the injectors, would they work ok for 1st 20-30 mins ? Same with the coil pack... Would it not be faulty on start-up as well ? Thanks for your help, by the way .. just been watching how to remove and test coil pack, and how to clean throttle body. 😁

No problem!

As @Tory-ing_Rob said, its possible that the additional heat created from running the engine could make them be a little less happy.

For example, my old Clio 182 would be fine on idle (after I had cleared the faults) but the light would flash up that it was unhappy after a mile or so. If I continued to run it on long journeys, it would just get worse and worse.

Let us know how you get on with a code reader