1996 X300. 152k miles on the clock. Been performing very well lately. Drove out to the western parts of Toronto at speed of 120km, 40 miles each way, returning 26 mpg. Just drove out to other side of the city. Going very well nothing unusual, had to accelerate briskly at high revs past a slow lane of traffic. Came off the highway and first traffic lights engine is missing quite badly at stationary. Gives signs of possible head gasket blown. Midnight here now and haven't had time to look. No codes showing, but if I remember the last time I had a head gasket go I wasn't getting any codes either and that was about the same mileage. At that time the head gasket blew over about 2 to 3 miles after a fast drive back in the UK at speeds over 100 mph and showed up quickly with a compression test. I don't think this car has had a head gasket before, but then who knows.So, question is, should I be seeing codes??? First thing tomorrow looks like I'll be head first under the hood....Ho hum.