yet another problem with the 240. ....ok...last night i had to make a "quick" trip Olds... get out on the highway and as im speeding up, im watching my RPM's go up to 4000...then i notice my car just lost alot of power, still accelerating, but i can feel it lose power, it does this in every gear. That worried me a little. I get everything i needed to and stop at Tim's for some donuts and an ice cap, theres a 15 car line up at the drive through so i park, leave it on and run in to an emty counter. Come out and my cars overheating. wtf? i left it running for about 10 min. and it over heats? so i turn it off and put the hood up to let more air get in and cool everything down. Temp goes down to where it should be and i start it up again. All is well till about 15-25 min. later it overheats just from idling again. Sit...let it cool...go for a drive and its fine for about 45 min...so i decide to head out on the highway, drive all the way home doing 120km/h and its fine, temp. stays the same all the way home. Anyone know what could be causing this? oh yea, it's an 89 240sx, and i just installed a new o2 sensor if that makes any difference. thanks.