An odd one.

[Guest]

6 hours ago, flash22 said:

Possibly fuel related, can you look at the misfire counter ? Do you run it on E5 or E10 ? Do you fill up at the same place ??

 

Where are you located ??

Staffordshire. Yes, checked misfire counters - all at zero. I run E5 and E10, Usually Shell, but occasionally Essar. I haven't used Essar since filling up with their E5 a few days ago. The poor idle started before then.

I have found a Youtube video, same engine arrangement, where the throttle body is removed for cleaning. Not as bad as first anticipated. It's on a 2010 Yaris.

He removes a small coolant by-pass hose but it's a bit vague because the next shot shows "plugs" fitted to two stub pipes on the throttle and another on the engine.

Does it require some coolant draining?

 

[TonyHSD]

10 minutes ago, olonas said:

Staffordshire. Yes, checked misfire counters - all at zero. I run E5 and E10, Usually Shell, but occasionally Essar. I haven't used Essar since filling up with their E5 a few days ago. The poor idle started before then.

I have found a Youtube video, same engine arrangement, where the throttle body is removed for cleaning. Not as bad as first anticipated. It's on a 2010 Yaris.

He removes a small coolant by-pass hose but it's a bit vague because the next shot shows "plugs" fitted to two stub pipes on the throttle and another on the engine.

Does it require some coolant draining?

 

That’s a good video. No need to drain any coolant. You can use 8mm bolts if you have any spare around to block the coolant hoses, this is usually what I do. Also no problem to push gently the plate open and clean around with clean cloth. And I use the same spray btw. 👌

[Guest]

19 hours ago, Rhymes with Paris said:

Probably sushi.

That's the culprit, a very fishy individual.

[flash22]

Other causes are OCV aka vvti solenoid or egr valve

OCV - if you do a few WOT snaps, and it either stumbles when dropping the revs or the engine falls flat on its face - check the resistance of the OCV

some cars have the heated TB, others don't