Messing with the honeycomb can really screw up your idle, it straightens out the air into the motor so the MAF can get a good reading. I took the honeycomb out of my 3000GT and had the exact same problem. Ended up putting it back in and fixing all the honeycomb wings.

 

hemm maybe just go get it tuned and raise your idle?

 

My cars idle will dip down sometimes but when it does it will go back up.My cars not even tuned and it runs pretty well.Im sure once I get the car tuned it will help my car a bit.

 

it sounds to me like a leak somewhere after the MAF, or the MAF is messed up. This happens in most cases when your BOV is venting to atmostphere and isn't being recirculated to the intake. I had this problem and corrected it by leaning out the idle. When did this all start happening?

 

^how exactly do you lean out the idle?

To the OP: this problem can easily be tuned out.

 

Guys, just my O2. Check spark plugs. They foul sometimes out of no where. Especially if run hard. It will cause those symptoms, as may be one might of starting to mis fire.