Well, it could cause your entire problem. Put it this way, that honeycomb is part of the mass air sensor, which tells the computer how much air is entering the engine so it can decide how much fuel to mix in with that. If it's damaged, it might read incorrectly, and the car will use too much or too little fuel, running too rich or too lean, which will definitely affect gas mileage, and if it was bad enough it would cause predenonation. Since your CEL isn't on, you're probably not in a serious problem, but you should have it looked at since the mileage is suffering so much.

 

I thought the same thing. My CEL isn't on so i'm not too worried since I know my car isn't going to blow up or anything; but next time I fill up and empty the tank i'm going to keep track of it and calculate my MPG and post here to see if it is reasonable. Thanks!

 

could u take a pic of the honeycomb for us to really see what it looks like, i dont think u hurtit too bad, as long as u didnt knock someof the comb out of the maf.