i have counter acted this problem 90%.throttle body bypasses on this car are a must !!.removing the rubber seal under neath on the front of the hood will allow air to get in there.just ask the bugs that i now collect on top of my air boxes.i have drop in filters and post maf tubes.i still didnt feel there was enough air getting to my filters in the stock box.so i opened the outer corners and removed the rubber that goes over the angled outer radiator supports.
i also copied another members idea on here that modified the front half of the engine cover for his catch can hose connections.doing this will also aid in heat escape from the pcv hoses not being able to add additional heat onto the im via engine cover.i bought the car used and i have made the car way more efficient by doing what i did.the computer on the car said i was getting 18.2 miles to the gallon when i bought it.
i now get or average 23 miles to the gallon in city driving shifting at 4-5k.take it for what its worth.i will add a pic for your reference.love it or hate it,these mods work well for me.air boxes still look stock when you pop the hood.also while its just a theory,i think the 02 sensors start messing with the fueling after they get so hot from this engine.i will add spacers to the stock setup sooner or later to test my theory.
EDIT;also in the 2nd pic,i have added cell foam pipe wrap on the maf tubes to aid in heat protection from the engine at idle.and when i can figure out where to put 2 catch cans on this car while keeping the oem air boxes,i will do that also.i know from experience on another car that besides the cans catching oil,they will also provide a little more cooler air going into the im.just dont know where i can mount a couple of small cans.
