: PO174 returns for an encore

06-05-12, 09:16 AM
I celebrated too early, it seems.

Got the CEL on the way home last night, checked it after pulling into the garage...no codes.


Put the code reader in the console, in case it happens again. Sho-nuff, it fired off another PO174 this AM.

Are there any vacuum hoses attached to the airbox which are below it? That's the only thing I can think of, now, though I did put a K&N in there, added no oil. I've done this on multiple modern cars, without issue.

I tried to get to the MAF, but was dying in the heat before I could get the intake tube off the engine side of the airbox so I could reach it. It's likely just stuck from heat cycling, but I don't want to break anything.


I'll check when I get home to see if I kept the old filter...don't think I did..., swap it out and see if that changes the behavior.

06-05-12, 10:09 AM
I didn't find the original post on this (other than the "Yay" one) but, I assume you've checked the intake plenum bolts....?

06-05-12, 11:24 AM
Yep, tightened those a few months back, but I should check again. I don't put the engine cover back on, so it'll be quick to do. I'd rather see even an ugly intake vs. a plastic cover, but that doesn't appeal to everyone.

I'm going to have to take all of the intake plumbing out and look at it...make certain I didn't manage to put a tiny hole in the tubing, somewhere.

I did put a K&N filter, a drop-in, in there, and that's only the second time the air box has been opened by me. The first was to merely check on the condition of the paper filter when I purchased it. Didn't disconnect anything to do that, just unscrewed the box halves, but the new filter required I loosen the engine side of the intake run, from the air box to the intake manifold.

I must have something together not quite right.

edit: BaTu, THANKS! It wasn't the intake manifold bolts, though I went through them anyway, and when I got to #7, when doing my best to not burn myself, just got home, and it's warm outside, I went to move a hose which goes from the left valve cover to...where does this go...oh, nowhere! Wait, here's where it goes...on the rear side of the intake ductwork.


Dude, I appreciate it. Part of the problem is, my garage is kinda dark, but it's so warm out there, I turned on the lights and opened both doors. My wife's car not being present meant more light.

06-05-12, 07:15 PM
Yep, I got taken in by that same hose myself. Oh well, I reckon I'm just a bit late with noting that to do you any good. :yup: