I would do the injector seals and the o-rings around the injector guides and see if that fixes the problem. That should be 2 hours labor and about $25 in parts.

Personally, I don't see how they could get more than 4 hours labor to do the gaskets and the injector seals. It's a lot of wrenching, but nothing complicated. I would say $500 tops.

It's pretty simple to test the intake gasket theory. Just get a can of carb cleaner or PB Blaster. Put the red tube in the nozzle. Pull the air cleaner, and with the engine idling, spray along the head-manifold joint and see if you get a change in idle.

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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