The first thing i would check is plugs and wires thats the most common reason on that car.Also is it worse with ac on?

saturntech9

Thanks for your quick response, it is kind of worse when ac/heater is on. I had the "same problem" 2 years ago, but my mechanic replaced the intake manifold gasket, it worked ok until the past 6 month started happening againg I also changed the spark plug. I took the car back and to my mechanic but he "checked" the gasket and the spark plugs and said every thing looks ok. I was thinking it can be a sensor, thanks again

I have replaced a lot of those leaking gaskets and have only seen them cause a miss at idle or a high idle never seen one cause a miss while the engine is driving under a load.Doesn't sound like a sensor how old are the spark plug wires?Thats the number one causes for those symptoms is plugs and wires i have worked for the saturn dealers for over 16yrs so i know those cars well.