Do you have someplace suitable OUTSIDE in which to work? Maintain eight vehicles without even a carport myself. Restricts you to fair weather mechanicing, but is imminently doable. Until you get some plugs out, does your exhaust system yield any combustion clues? Any residue, dry or wet, in the tips? Let exhaust bounce off a piece of white paper held by the tips to see what it catches. After dark, shine a flashlight beam across exhaust flow to highlight subtle smoke not visible in broad daylight. Cap off all vacuum devices as you diagnose (mode switch is powered by 3/8" takeoff on passenger intake rail). Remember that not all vacuum leaks are located at hoses. That's why you need some spray carb cleaner to check various manifold connections themselves. BTW: what kind of fuel economy are you getting? If your engine is mistuned, you should see big drop. BBTW: David T is correct -- you should use EITHER idle speed motor OR brass screws in upper air assembly, but not BOTH. Can switch back and forth, but only one idle system at a time. Your questions in order: 1) I prefer low resistance plugs with high voltage coils. Allow as close to full voltage as possible to jump bigger gap (spreads more fire around cylinder). Also allows timing closer to TDC. Don't know if "performance" plugs can do the same. By the time juice has fought all that resistance, what's left to ignite the fuel? On a properly tuned engine electricity is all you need. My plugs are 6 ohm Delcos gapped .38". 2) Timing is adjusted by rotating distributor. LOOSEN (not remove) the hold down nut (11 mm) and move entire unit. Rotor button moves with camshaft, so what you're adjusting is relative position of spark plug terminals to camshaft position. Access rather difficult with idle speed motor in the way (sorry, couldn't resist) but doable with long pattern flat wrench. Timing mark is a notch on crankshaft pulley, measured against scale bolted slightly on passenger side of block. My engine timed 10 degrees BTC. You don't touch intake manifold (can't -- engine has to be running). 3) Fuel mixture screw isn't poisonous -- you CAN touch it (see message #32067). In fact, regarding recent threads Re: disabled Lamda system, imagine would need to adjust for altered fuel distributor dynamics (lower chambers). I just wouldn't look there first (unless someone else has been turning it...) 4) Have never adjusted PRV valves (actually tappets that push on them), but don't look any different from other adjustable valve trains. Time consumed isn't going to be actual adjusting -- is going to be digging down to valve covers, then putting everything back. You'll also lose time removing/replacing muffler to access big nut on crankshaft to turn engine. Rotate timing mark to TDC on compression stroke (watch cylinder 1 intake valve to open & close), then adjust valves identified in tech manual. Tappet adjusts just like idle speed microswitch bolt on throttle plate bracket. You want feeler gauge to BARELY scrub tappet and valve stem. Will adjust half of intake valves and half of exhaust. Then rotate engine 360 degrees and adjust other half. Gaps are in tech manual. Moderator may not let all this through (besides, I need to GET BACK TO WORK!), so email me direct (brobertson(at)carolina.net) if you want to discuss further. Stick with it. Unless engine hopelessly worn or cracked, you're just dealing with out-of-tune adjustments. See now why I recommend doing your own mechanic work? Bill Robertson #5939 >--- In dmcnews@xxxxxxxxxxxxxxx, "therealdmcvegas" <DMCVegas@xxxx> wrote: > After running thru a little "cocktail" comprised of Berryman's Chemtool, and > Bardhal FI detergent, the engine actually did indeed run cleaner. The HC's > dropped down to 380ppm at idle. Unfortunetly, that still means that it failed. > Sooo, I tried adding in some denatured alcohol. Lo and behold, the emissions > became worse than before!!!!! Dammit! Maybe I did something wrong, but I've > had it up to here trying the "better living thru chemistry" route of automotive > repairs. I'm not going to put my motor at any more risk by trying to run > distillates and detergents thru it. > > So it's back to the drawing board, and doing what I refused to admit that I had > to do before: actual repair work. [Moderator snip]