A quick note to anybody suffering from a bit of rough idle... it may not be completely your valve springs. I was still getting a bit of random roughness and vibration at idle after the valve spring job, it's been much better since, but I still noticed it at times.

I decided to take a look at my MAF for the hell of it today, when I removed it from the intake the o-ring that seals it literally broke into two pieces. I tried to remove it carefully and I found one half of it but I don't know what happened to the other half. I probed the inside of the intake a bit to make sure it didn't fall in there but didn't find anything so I hope it just fell into the engine bay somewhere.

Anyway, I got a new o-ring - surprisingly they actually sold it as it's own part # I was worried that it was something that you'd have to get the whole MAF assembly for meaning a probably frustrating search through the plumbing section of hardware stores for something that was a near match. I put the new o-ring in tonight and, while it's obviously too soon to tell just idling for a while parked it was rock solid and I didn't feel a single odd vibe any more.

I guess the bad ring was letting a little unmetered air in, not enough to throw any codes or cause any real drivability issues (or for that matter even get noticed by the techs that have had my car hooked up to techstream quite a bit over the last few months), but enough to make things run a bit odd at idle sometimes.

I've done my share of messing with MAFs on my cars with intakes and OCD cleaning rituals but I've never seen an o-ring just fall apart like that. I'm not sure what could have caused it.

 

Good info. That could definitely be the culprit.

 

Pictures of it would be great if you find the time for it.

 

I guess the time has passed for that... but really, pictures are totally unnecessary unless it's just for curiosity. To get to the MAF, you just need to remove the passenger side engine cover, remove two small screws on the square box sitting on top of the intake immediately after the airbox and pull up. You can literally get to it for cleaning/inspection in about one minute.

 

Hey jay where did you get the o ring from

 

^From the looks of it, he got it from the dealer. I don't suspect you could find the exact piece any place else.

 

Thanx cause I have a rough idle, when im at a light I gotta put it into neutral to smooth it out

 

I need part # please. No where to be found on the Sewell's diagram

 

I have no idea any more. I'm pretty sure I didn't look it up myself, I think I just went to the parts counter and told them I need the o-ring for the MAF and they ordered it. If you just get a big box of random sizes o-rings (which I have bought since doing this just for future random use) you may find one that fits closely enough.

It's cheap, just ask the parts counter.

 

binaryjay, i have an 08 GS460. I have been feeling the idle to be a bit rough when at a complete stop. it happens every so often but its noticeable. The car had the necessary repairs done on it for the piston ring work back in 09 but I am wondering if the MAF o ring may be the culprit of what I am feeling. I know very little about mechanics and components so this is all new to me. check out the the attached photo, is this the component attached to the MAF in which I need to remove the 2 small screws and where I'll find the O ring? Thanks.

 

Nice, good to know. I might have the same problem.