CEL on and no code

[Nordic92]

finally I got time this week to work on it
I replaced ECU and MAF with tested ones: both good; problem is not there

reminder:
engine goes good couple minutes, then CEL turn on : 34
engine runs so-so, if I open throttle slowly it will go in high RPM but if I hit the gas pedal fast or let it go too fast, engine wants to stall
code 34 is telling that there is a problem with the air intake and symptoms confirm this but what can it be?
there are many hoses, valves, sensors all around the injection: can it be that? but no idea what they are all about!!!

and finally, here is a picture of the Canadian tag, with the maple leaf


I hope to find soon! really miss driving it!! thanks