OK guys...newb here! My parents have two volvos...a 96 850 n/a and a 90 740 GL or GLE (I forget, non turbo though). I myself am an Acura technician so I know my stuff pretty well however i'm kinda stumped right now. my fathers 1990 740 n/a has been experiencing a loss of power for a couple of months now and we can figure out what the hell is wrong w/ it. sometimes it will stall out while idling but for the most part it has no power at all under 3000 rpms. If you start in drive from a stop and step on the gas it takes forever to climb speed. but once you get to 3000 rpms it moves....however if you just leave it in drive...the trans will upshift like normal before 3000 rpms, so my father has to start in 1st or low and manually upshift himself to try and keep the rpms quite high so he has some power. I've driven it a couple of times and it gets pretty scary on how little power it has. We've done the normal tune-up maintence like spark plugs and cap and rotor, fuel filter and such. We even had the catalytic convertor replaced because it was collapsed inside...and still nothing. no check engine lite is on. WHAT CAN I DO??? I've searched for a chilton manual at all the local stores and can't find one anywhere. Is there anything that could be causing this like a sensor or something...something common maybe??? Any help and all help will be greatly appriciated. Thanks in advance.