I've isolated at least part of the air leak to either the manifold gasket at the number #4 runner, or the #4 injector outer seal. If I spray carb cleaner in that specific area my idle changes noticeably. When I get as precise as possible with my aim, and carefully squirt a little carb cleaner between the injector itself and its plastic holder, and not spill any over the edge of the holder, I get no change in idle. Basically it's pretty hard to tell for sure. It might be the outside injector seal, between the plastic retainer and the head. Or it might be the manifold gasket at the number #4 runner. It's hard to be precise enough with the carb cleaner to separate the two places because they are so close together. Any ideas on how to diagnose the leak more precisely. I don't really want to do both jobs if only one is necessary. Can RTV High-temp Silicone Gasket Maker be used to temporarily seal the top edge of the manifold gasket? Or is this going to cause a hassle if I end up replacing the gasket? Any recommendations on gaskets? Last time I had the manifold off, FCP sent a gasket that had no name on it. Previously I used one marked with the Elring name. Would one purchased from Volvo be the same Elring? I'm not using a no-name gasket again.
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Thanks to all for the help. 81 242 Brick Off Blocks, Turbo bars and wheels, B21F, M46; 86 244, 142k , auto.