Hi All,

Vehicle perforamnce is very flat at all times , occasionally a slight surge of power about 3000 rpm then it drops back again. Occasionally on full throttle MIL illuminates and code 0234 is stored.
Live data shows max boost of 202Kpa , turbo actuator moves freely with vac applied , vac pipes checked for leaks , all ok. Have driven & applied vac to actuator with mityvac , can raise boost to 240+Kpa on live data but performance still poor.
EGR looks clean , loosened exhaust at downpipe , no change.
MAF live data ranges from 1.9v at idle to a max of 3.6v at full load/revs , this seems low to me but why would a MAF fault cause the P0234 fault code?(MAF is a Bosch unit).Looks like the air-filter has got wet in the past because is crumbling & some bits of filter were in the MAF gauze.
Have also smoke tested intercooler / turbo hoses etc , no leaks found.

Can anyone confirm the correct max boost & max MAF figures for this engine (same as Vectra 2.2?) ,any other suggestions welcomed

Thanks

Andy

Edit - Been thinking about this further and obviously as your question pointed out the petrol is throttled while the diesel is not , so my first statement is incorrect! Therefore is the MAF signal used in conjunction with boost pressure signal to correct fuelling for boost variation. Funny how a simple question makes you question what you thought you understood!