So I dropped pots this morning. Ran fine out then 9 mph coming back. Just would not go any faster. So the windows started to fog and I turned on the blower - Poof, fixed, power and running fine. Turn blower off, loss of power and RPM. It is a Volvo 5.0GL. The GL stands for "Good Luck". Temp was fine as well as everything else. What on God's green earth does a defroster have to do with engine power????