get ahold of an OBD-II, some part stores will read it for free. thats where I started, it said missfire, so I started with plugs, when I went to change them the sparkplug wire fell apart in my hand, so I "african-american rigged it" back together, went back to the part store and bought new wires. and it was running better just from me fixing up that one wire, so I changed all the plugs and wires, and presto! Good as new.