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OK so far have tried a new fuel pressure regulator and no change. Then tried 36lb injectors and still no change. So now am thinking maybe the fuel pump is tired and can't keep up? I checked the current drain of the fuel pump with the engine off and its 5.8 amps. Should I suspect a bad fuel pump with such a low current draw? All the pumps that have failed on me in the past have either stopped working altogether or kept blowing fuses.

best way to test is a fuel pressure gauge look for pressure dropping when it goes lean if it keeps rising pumps fine

does the engine misfire/shudder or do anything abnormal when the 17:1 ratio is being read? cause ive had situation where it was a exhaust leak at the flange gasket of the exhaust manifold wasnt sealed correctly and at the same point of accelleration 20% or so ... found it was sucking in small amounts of air every time the valves opened and closed made a negative pressure sucking in the air and o2 sensor was reading lean but car was running perfect no matter what i did it always ran lean at that point as soon as i resealed the flange it was perfect ????? dont know if its the same as your problem but....

Have you moved the MAF or messed with it in any way?

It runs very smooth even when lean. However once I see lean on the wideband I back off straight away. The sensor for the wideband is in the left bank and the gauge has a narrow band output which is connected to the ECU, so if the gauge reads lean then the ECU is also getting the lean reading, for the left bank at least.

Doctor Bob.. The MAF has been moved. It located about 2.5 feet away from the throttle body and in between the throttle body and intercooler. 2.5 feet is as close as I could get it with 3 inch piping and not having it close to the exhaust.

Thanks everyone for your help... turns out it was a dirty MAF!! Anyway if anyone is interested in some cheap injectors and fuel pump let me know.

was heading in that direction, was my next question.lol
glad its sorted

shame you had to spend so much money trying other parts to find it!!

just as a bit of a side question to this .... is there any hard and fast rules ? ie. does holden normally clean these at certain service intervals or is it the sort of thing that would only be cleaned then it plays up ?

i cleaned my maf when it was installed with the v6 conversion, but thats well over 30,000kms ago ?!?!?! ... might try cleaning it soon and see if it makes any noticable difference or improves economy etc.

ive seen many a dirty maf even on cars that were serviced by holden cause horribly low power, it causes it to read less air which makes it lean AND more spark advance so it hits ping territory which makes the knock sensors go off then reduces timing. you usually see enourmous improvements if it is dirty

This maybe a silly question how do you clean a MAF?