My car is a 1996 infiniti Q45. I am trying to identify the problem. my car has been stalling intermittent. but the other day is start bucking at speed of 75 mph ,to the point that when i press even more on the accelerator the RPM didn't increase or move up at all. Then it kicked in for two minutes and then start bucking again. Both times the RPM gauge did not increase when I depress the gas pedal. Also the engine did not rev up with the gas pedal depress. Is this a Trasmission problem symptom?