Scratchy head?

[bluepain]

I recently posted on my 2.0l having a lumpy tick over,...
Plugged in my code reader and got the codes below..
So it seems I have an air leak from what its saying,which makes sense for the hesitation from idle to throttle..
Would I be right in assuming that the issue will be the engine side of the MAF as opposed the the filter side ..I'm assuming this because if the leak were on the air filter side the maf would calculate the air mass travelling through it. And adjust fuel accordingly?..
Ware as if the MAF has calculated air mass and there is a leak past that then the ratio will be out and a misfire will occur..
Scratching head here now?..
I cant see any visible leaks or tears..are there any problems areas to check before I get it booked in for a smoke test..
Or is there something else causing this confusing the car and myself....
Cheers again..

 

[colb]

Looks like a leak after the Maf is the cause for setting those codes, smoke test is best to find any that you can't find doing a visual check of all the hoses and pipes. With smoke look closly at the cam cover if its a plastic one, found one cracking and breaking up around no4 spark plug and letting unmetered air in. Also a leaking sucking air jet on that one (2.2) thats just below the throttle body clamped to the side of the engine block. If yours has a dipstick check that as well, the O ring in there turns brittle and leaks air into the sump. A look at live data Fuel trims will also point to an air leak being present, the car will try and compensate and add fuel at the injectors, it will keep doing this until it reaches at least 20% more fuel then give up and set the EML on the dash to draw attention to the fault.