Mitsubishi Repair: 2001 Eclipse not reving past 45k-55k, rattling sound, speed sensor

Question
I a have a GT Spyder that in every gear, between 45k-55K rpm the vehicle revs down and there is a hissing sound coming from the engine compartment.  If I give it more gas there is a bad rattling sound accompanying the hiss and the vehice still will not rev up.  It drives fine other than that and shifts smooth.  Please dont say tranny problem!

Answer
Alex: I think you have a sensor problem, such as the speed sensor. In that the computer is reading things right or the speed sensor is not telling the computer right. But that is a bit to do with the transmission. Opps, I said that word. lol. Well sorry, I shall try to check on line later to see if there might be a recall on this or some other GT Spyder owner had this problem. But mean while you could go someplace to have your car coded to see if the computer might kick out such a problem. I always say if the transmission is still shifting that is a good sign. Oh hey is this an auto or a clutch? Auto have you checked the fluid? If so might need a fluid and filter change. A clutch well then it could be a problem with the clutch. Well I will try to look into this more today. Hope this helps some and good luck! Linda