if your fd felt great at throttle but crappy at idle it would be...
 

? this car feels good at WOT but at idle the boost and A/F gauges bounce and the idle is all ate up. the A/F gauge will just keep going back and forth and the boost gauge shows the vacuum bouncing between like 14-18. its my buddies car just curious what y'all think.

Blown engine! That's the telltale sign of apex cracks, is if the vac fluctuates at idle, but the RPM does not. It can still pull pretty hard and rev high....but not for long.

I could be wrong, since i've never had a broken engine, but that's what i hear.
~Tom