Just finished the same job myself. Fun isn't it :-)
I found mine was jamming against one of the hoses at the rear and I had to remove this to get it back in. It's the one that comes out upwards on the drivers side at the rear corner of the plenum.
Thanks for the reply, did an oil change too, more laughs!
I've got the plenum in place, lined up with the intake runners, but the plenum doen't seem to want to move forward to slide the rubbers on - do you start from the left and attach sequentially?
Dumb question I know, but it got late & I was losing my rag
i had a problem with this when i did my plugs, i found working it in on an angle starting on the left then pulling the right in did the job eventualy (lots of force needed to get the rubbers to flex into place) took ages of pushing ang pulling but it does go back on, i promise
that was the single worst job i have ever done on any car
it was about midnight when i finaly got it back on, (started at about 7.30 pm)
Mine went on easily enough, maybe I'm just lucky!
Maybe try tilting the plenum a little as you push it in.. I had mine tilted forward slightly (top of plenum going towards the headlights) so that the tops went in first and then it slotted nicely into all the rubbers at the same time.