Allow me to first say that this "possible" failure may not even be a failure, but rather a design flaw that may or may not have been encountered by others on this forum. Secondly, if it is a failure, it is not even close to how the L36 UIMs fail.

Now with that said...

I was working on the '94 SSE yesterday evening, hood open, engine running (checking for lifter chatter), and slight hand-induced movements to the throttle. Something caught the corner of my eye when I did this, and I was thinking "no way in h3LL". So I repeated blipping the throtte, watching the UIM. And sure enough, it happened again. What you ask? On the "front" of the engine (that would be the 1-2 cylinder side), near where the PCV valve is (I think it'* a PCV anyways...same location where the MAP would be on an L36), the whole "front" side of the UIM flexes when giving it the gas. And I wasn't goosing the throttle all the way either...it was more like reving to say, 3k then back to idle. It'* flexed for so long that stress cracks, or what appear to be stress cracks, have formed.

Current mileage is @123k. Pics and video will follow later this evening.

Has anyone else noticed this on their L27'* with composite UIMs?

my old upper on my L36 did the same the middle bolt was loose and the upper would move a each time a gave throttle to it like it was breathing .but had no leaks so i just gave that bolt one more turn. and later i found 2 more hidden bolt where loose when i change my upper

Battery was dying on me, so I couldn't get the hairline crack pics, but here is the video that shows just how much flex there is in this manifold.



It really isn't all that bad, but it is more than I like.

did you check youre bolts on the sides mine were loose like the where finger tight