i have been working on a 98 s90 at my shop that won't idle up under load. when you turn the steering wheel all the way, the car dies. it happens more frequently when the a/c is on. i've replaced the idle control valve and scoped the m.a.f. sensor, the e.c.t. sensor, and the t.p.s. and all scope good. i am at a loss as to what to look at next!!!!