Hello guys,

I've had my freshly imported JDM Evo 8 MR for around 3-4 months now. She's been perfect, hasn't skipped a beat (yet). However a week or 2 ago the engine started 'dipping' when idling. Still drives perfect and doesn't do it on cold starts.

The car is basically stock except for an Apexi air filter and HKS backbox. No engine performance modifications or anything like that. She's got +/- 167.000 km's.

I've already taken off the MAF to clean it (wasn't even dirty at all, still cleaned it as best as I could). Does anybody have any idea what this is and how it can be resolved? Spark plugs maybe?

I've attached a video of the dipping, which makes sense I hope. Thanks in advance guys!

Edit: I couldn't get the video on here, so I uploaded it to Vimeo: https://vimeo.com/554330557

 

Check: Plugs & coils - because of the intermittent misfire. It could also be a sticking injector, although this is less likely. Finally check that the IACV is moving smoothly in and out.

 

Thanks a lot for the tips. I replaced the plugs today however it didn't change anything (BPR7ES). How can I best check the coils to find out if they function correctly?

I came across a topic on here with regards to testing the IACV, which I will definitely do, thanks!

Also, if the IACV has to be replaced, where can I best purchase it from? I see it ranging from $50,- at NPBoosted all the way up to $420,- from STM.

 

unplug the lambda sensor and see if it runs stable

 

I did find out today I probably have a bad exhaust manifold gasket. I washed the car today and opened the hood right after just to check over some stuff when I saw this:
Definitely not looking forward to changing that one LOL.

 

That doesn't look or sound like an exhaust manifold leak. It looks like water boiling away due to the heat.