hello
i removed and cleaned the throttle body and iacv (due to engine stalls after revving it, it's sorted out now) and saw that the intake plenum is quite gunky inside.
is there a point in dismantling the upper cover and cleaning it, as well as the egr passage and valve? there isn't any fault code.
i guess the lower part mustn't be cleaned without removing it from the cyl. head or else all the gunk will get where it shouldn't.
thanks

 

Seems like the EGR passage would be the thing to clean, and that's in the lower section. But it should cause some symptoms if that's blocked.

Your judgment whether its enough gunk to warrant, but you may as well open the plenum & see. If I remember from my 1998, you can't get the manifold off the head unless you remove the top of the plenum first. There's also a brace that you unbolt from below the car.

 

Yes, remove the upper plenum, and the EGR valve. Then clean the build up where the EGR port enters the plenum (Intake manifold halfs). That's where you'll see the most build up. When I did my wife's 00 Accord, that's where I found the build up. I had tried to use a piece of braided wire (cable) to clean it first, but the curved transition from the EGR mount to the plenum is very tight. That requires the upper part to be removed to get it clean.

For the engine side of the EGR port, I just hit with compressed air, as it was open and flowing (dumps into the exhaust port/exhaust manifold).

 

and what are the two small holes at the bottom of the plenum?

 

Could you link or post a picture?