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Exhaust/Engine flutter at warm idle

3.5K views 9 replies 4 participants last post by  tibby  
#1 ·
Been noticing this recently - slight hiccup, or flutter on warm idle. Doesn't do it when cold, and otherwise drives fine, revs through cleanly.

Mainly noticible through the exhaust, but in the cabin you do get the slight 'miss' and a change in engine note too. Don't recall this happening before, and not sure if it's just my paranoia feeling like it's getting worse recently! I'm due a service in about 2 months, but interesting to note if it should be looked at before then.....

 
#2 ·
Year?
Miles/KMs?
Tune stock or aftermarket?
What service is due?

Doesn't do when cold? O2 sensor at cat is not doing diddly at cold idle, but it comes on line when warmed up. The rough idle is typically when the air/fuel mix is most sensitive, with the engine clinging to revs. Could be the O2 sensor.
 
#4 ·
2017, 65,000 miles, stock tune - and just an oil change due next, had the major last year. Always run on SUL too.

Not when cold, only when warmed up. Could be the plugs, in theory they're almost due again based on mileage....
 
#6 ·
The O2 sensor isn't on line when cold. When warmed up, and the problem occurs, the O2 sensor is on line,

Of course, you should clear all variables if they're due anyway, such as plugs.
 
#8 ·
Update - this was in fact, faulty plugs.

They'd actually only been changed 10 months ago (important - always check the service history :LOL: before buying stuff!) but seems they may have been faulty after a chat with the guys who changed them. Sure enough, replaced and now idling smoothly. Can't say I've noticed any real change in performance, but still, an easy fix :cool:
 
#9 ·
Actually a further update on this - I've been told they may not have actually been faulty...but fitted incorrectly and not torqued up enough, leading to a leak on the gasses (see second plug down)

Image


Bit sad if that's the case, will have to speak to the garage.
 
#10 ·
Actually a further update on this - I've been told they may not have actually been faulty...but fitted incorrectly and not torqued up enough, leading to a leak on the gasses (see second plug down)

Image


Bit sad if that's the case, will have to speak to the garage.
Or overtorqued, which leads to a stripped / damaged plughole??