G60's been sitting for 9 months n doesnt run properly???

[g6092 0]

Hi, Ive looked around but can't seem to find what I'm looking for (am new to the forum). I have 2 G60's that have both been sitting garaged for 9 months and 6 months respectively, the problem I'm getting is that both engines start and run fine, but when you try and put any power through them they seem very unwilling to move. 3500-4000rpm is the most you can get out of them but for the revs given in any gear the output is well down. It isn't lumpy or missing, progress is smooth but almost asthmatic. Have tried all boost hoses, leads arm and cap, sparks, chargers whistle (stage 4) but where that power goes is starting to get the better of me. Any help would be greatly appreciated, Dom.

[steveo29 0]

stale fuel?

[g6092 0]

No i put £20 of new fuel in and no change!! I still have no idea's?

[shamstar 0]

Blocked fuel filter??? Sticky ISV?

[g6092 0]

New fuel filter is on, isv has been blown thru with carb cleaner, still juddering and inconsistent under load. At idle in neutral, its fine...1st gear seems fine, 2nd and 3rd are ok under 2000rpm but normal driving up to 60-70 is near impossible let alone 'having a fun drive' :confused4: