Ok, for the benefit of those ppl having poor idle, performance or fuel consumption, here's a snap out of the vl book showing how to interpret the red and green flashing indicators, as it relates to O2 sensor and mixture control. It may help you to prove wether or not mixture is the cause of a 'miss'-behaving engine Note: These codes are with the ecu in normal mode, not diagnostics mode. There are a few engine operating conditions where the ecu will not operate in closed loop mode and both red and green indicators will be off anyway. They are [reprinted from the book]: 1. When starting the engine 2. When the engine and oxygen sensor are cold 3. When driving at high speeds or under heavy load 4. At idle 5. When the oxygen sensor detects a too lean condition for more than 10 seconds [i.e. fault condition] 6. When fuel cut-off function is in operation [decelerating] I can't quite get my head around the wording of No. 5, certainly what is true is that either extra rich or extra lean will cause both led's to be off. Bear in mind also that if you are achieving at least No 2 or No 3, then the engine should be running fairly good if all else is ok, especially in the case of No 3 [rich], No 2 [lean] may result in the occassional misfire. Getting it to 'optimum' is for the benefit of the cat converter, as they only work when the mixture is very close to stoichiometric [14.6:1] If you need/want to adjust your afm, then you need to pop the plug from out of the round protrusion just to the left of the afm connector. Mine was not 'popable', I had to drill a hole in it. Be very carefull doing this though. At the bottom of it is a small screwdriver adjustment potentiometer. It is a 'many turns' type adjustment [typically 10 turns] and, at least for the bosch type, you cannot rotate it too far and break it, they have a built in slipping clutch when you reach the limit. Clockwise for leaner, counterclockwise for richer. Another reason I'm posting all this is cause I too have been going in circles with a poor idle misfiring engine, which has been proven to be a too lean condition caused by low fuel pressure. Wether it's the pump or the fuel reg I don't know yet. I'm pretty sure it's the pump, as the fuel reg diaphram is ok at least. I can put another piece of hose on it and suck as hard......ummm 'apply vacuum' and it not only holds vacuum, the engine rpm drops and it starts misfiring badly again. I've managed to temporarily improve my situation by removing the vacuum hose off the fuel reg altogether and block off the hose, and to adjust the afm fully counterclockwise [full rich]. This has given me a near perfect idle but I can still only just achieve No. 2!! Some original photos have not been recovered yet.

think this should be sticky (at top) then I'll add a few hopefully helpful comments,