Ok heres the deal, my check engine light came on about a month after owning my car ( traded a gas guzzler for a 96' 200sx 106,000 miles ) the car was slightly shuttering when accelerating so i thought hmmm.... spark plugs so i replaced them, light went off. Now my car is doing it agian i replaced the plugs again just think it worked once maybe itll work again, it didnt so i went and got my computer checked and it said pressure below threshold the mechanic said it something in the exhaust. O2 sensor is what im thinking. the car is also giving off a little smell kinda like a clutch when climbing rpms, once im stable its all good. any ideas id really appreciate it.