87 GXL, sort of feels like the car stutters at low rpm (around 1000) when the car is fully warm. The car shakes pretty violently. You can feel it when turning the engine on and off as well. Also, I am getting really low mileage, around 10mpg. I have replaced egr valve, spark plugs/wires, air filter, oil, o2 sensor and the timing was good. I know i have a pretty big exhaust leak, maybe this is the cause? But, what else might be causing these problems? Thanks for your time.

 

I got pretty poor milage also with leaks I had. A few cheap gaskets had me all fixed up. It really sounds like you have a vac leak somewhere and that would be a worthy first place checkout.