Rough idle

[RichyH]

Is there any reason why my LCR sounds a bit rough when idle? Sounds a bit rough from the outside, and feels a bit rough inside? Not as rough as coil gone for sure. Thought about getting the engine flushed out from all the carbon build up to help? But last resort il just go to a performance garage


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[andycupra]

there are many things it could be.
i presume the usual applies in that you service it well, plugs, oil filter all good.

MAF contributes alot to running, so try unplugging this and see if it improves, if it does it may point to that,.
check all vacuum hoses.
inlet pipes filter etc. just to rule out obvious before you start throwing money at it

 

[Calumcjm]

Mine was a bit rough and lumpy as well. Cleaned the throttle body and realigned using vagcom which made a noticeable difference, so that could be a cheap option.

I'm pretty sure engine carbon cleaning cleans the throttle body too but I could be wrong

 

[Klaus71]

I'd agree with what Andycupra says, check the cheap fixes first. I didn't think I had a rough idle until I recently found an air leak in the pipework under the intake manifold which in my case threw up a eml every now and then. Fixing this helped things nicely but when I changed the plugs that made a huge difference. The old plug gaps were all over the place. New ones correctly gapped has really smoothed things over.

It's free to pull the plugs and check their condition as is having a shufty under the intake manifold for squidgy split pipework. These engines are never going to be rolls royce smooth at idle but a definite occasional engine judder indicates something could be better.

In summary,

 

[RichyH]

Cheers, yeah its well serviced, has a major service twice a year plus the MOT obviously, decent engine oil, super unleaded petrol, i have spare plugs ready so thats not an issue, is there anything visually different if they are spent?


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[mty12345]

+1 for split PVC pipes, also check that the dipstick tube isn't broken as that has the same effect.

 

[RichyH]

After a quick hood pop after work, The MAF out doesnt make a difference, can't see any split piping, the major intake/coolant pipework is forge m silicone not that old, the hesitation noise is coming from the left side of the engine block, looked at the timing belt but that all looks normal.

At idle its smooth and then a hesitation or stutter and then smooth again, drives fine just worried this could develop into a major issue


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[Aidan1105]

RichyH did you manage to resolve this issue? I've also got a smooth idle then a hesitation then back to smooth again, it normally happens after I've been driving, its not an issue first thing on a morning...

 

[Connor H]

RichyH did you manage to resolve this issue? I've also got a smooth idle then a hesitation then back to smooth again, it normally happens after I've been driving, its not an issue first thing on a morning...

Unlikely he will reply to this thread, but i would go over all your vacuum lines/system. give them a clean and check for splits or loose clamps etc etc