4.2 Engine Smoothness

[romeodelta]

It's hard to describe, but I'm experiencing a slight miss/vibration on idle. I can feel the sensation through the seat and the pedals.

There is a very slight fluttering of revs, but otherwise runs well and no codes.

Is this a characteristic of the engine, or is there something more sinister?

I'm planning on changing the oil to see if it improves and I think the valve cover gaskets need doing, as I do smell a slight burning occasionally. Oil level is good and stable.

Thoughts?

 

[philw696]

That needs proper investigation as soon as possible.
It could be as simple as an engine mount but if the valve covers are coming off you can have a look at the chains and guides to a certain extent.
Good Luck.

 

[conaero]

Check the basics first. Oil level, see it a lot, over filled causes vibration at idle. See this time and time again where service centres fill it to the top line when changing on a cold engine, then don’t check it hot.

Best rule is put in 7.5L when changing, hot idie for 5 mins then top to suit with the final litre.

Engine mounts as Phil says, get underneath, if the engine mounts are not domed and more flat, they have failed.

The burning smell will be leaking camcovers dripping onto the hot cats.

As for unsteady idie, prob the oil level but clean out the throttle body with brake n clutch cleaner and check the intake pipes very carefully for splitting and make sure your intake actually has the large metal clips and the pipes to TB are on at the bottom.

 

[romeodelta]

Thanks all.

Engine mounts were mentioned on the last service, so will get them checked out as well.

 

[spkennyuk]

Is the uneven idle just after start up or anytime that it is at idle ?

If it is just at start up then the secondary air system could be leaking as well.

 

[A.S. Motorsport]

Check the basics first. Oil level, see it a lot, over filled causes vibration at idle. See this time and time again where service centres fill it to the top line when changing on a cold engine, then don’t check it hot.

Best rule is put in 7.5L when changing, hot idie for 5 mins then top to suit with the final litre.

Engine mounts as Phil says, get underneath, if the engine mounts are not domed and more flat, they have failed.

The burning smell will be leaking camcovers dripping onto the hot cats.

As for unsteady idie, prob the oil level but clean out the throttle body with brake n clutch cleaner and check the intake pipes very carefully for splitting and make sure your intake actually has the large metal clips and the pipes to TB are on at the bottom.

Totally agree, the oil level is such a common on dry sumps.
What we often see if some one DIY's or over fills especially a drysump (02-07) is that oil finds it's way trough the vapour return on the MAF sensor causing all kinds of issues.

If it starts triggering errors it's often the larger vacuum/vent hose left side of the intake manifolds the hose clamp comes undone, same for the small one on the right side (there was a change very late as the new hoses that come from Italy are extra secured and sealed)