Hmm. That's the hose that feeds the air injection pump. It is routed through the air cleaner (the big silver piece) so the pump will get filtered air.

The function of the air pump is to add extra air only while the engine is warming up. It really doesn't matter one way or the other if the hose is connected to the air cleaner or not. It's not like it's a vacuum connection.

So (a) the hose and pump are relevant only during warm-up and (b) it really doesn't matter if the hose is connected, except for filtration.

I am glad your problem has gotten better, but I don't think connecting the hose had any effect. I suspect your problem will occur again.

I suggest that you remove the air cleaner and take a close look at all of the vacuum connectors and hoses.

Good luck.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe