Could you ask a few MORE questions in ONE post... I just replaced my cap/rotor/wires/etc. Found access very easy by removing upper air assembly (with fuel distributor still attached). Is only held on by 3 bolts (two 6mm's through brackets on the intake manifolds and a 10 or so through the butterflies). Also took opportunity to relocate idle speed motor in less congested part of engine compartment (makes access to spark plug 4 MUCH easier). I simply capped off the original supply line and gave the motor its own breather. My particular PRV has the idle speed motor hard wired too (courtesy of Goober, the friendly neighborhood Volvo mechanic -- I'm burning a replacement block). Microswitch is missing altogether. Except for additional wear on motor, presents no problems. Experimented running car without it: no sweat, just adjust bypass screws otherwise not "f_cked with", but you do need to set rather high to compensate for A/C compressor load. I decided was smoothest to put the motor back in (now screwed to the side of the compartment). Assuming my throttle assemby is stock, idle speed can be at least partially set with a bolt & lock nut that cracks the butterflies. The screw you speak of between the air plate and fuel distributor is a mixture screw (it adjusts plunger movement within the fuel distributor). Mixture is also adjusted on the fly by a frequency valve (also missing on my PRV -- gee Goob, loose anything else while you were in there, like a wrench inside one of the manifolds?). I could point out that a LEAN mixture burns hotter than a rich one, but risk angry replies from DMLer's who think otherwise. When you replace your vacuum hoses, I suggest using fuel line rather than traditional hose. It'll hold up MUCH better. If your car idles smooth already, you probably don't have any leaks. Vacuum leaks show up at idle, and there's nothing like 'em (pull one of your current hoses loose and you'll see what I mean). Unless you've got mold (don't laugh, I did, courtesy of a pinched A/C evaporator box drain tube) the only green substances in your car should be antifreeze and freon. Since freon evaporates very quickly, that narrows your choices. Antifreeze outside the engine is bad. As Martin G observed in another thread, is a symptom of another potentially large problem. Exactly where are you finding this residue? Bill Robertson #5939