Jimm 1/19/2013Check the spark plug boot - maybe one has become loose or disconected at the spark plug. If these are OK and installed correctly at the spark plug - then check the coil-on-plug wiring and connections. The condition and spark plug coil-on-plugs (COP) are usually checked / replaced at the time of the tune-up.
Check the many on-line auto parts sources, such as; www.autopartswarehouse.com or www.rockauto.com for the replacement parts.
For example, they (RockAuto) list the coil-on-plug from around $27.00 each for your vehicle. They are not difficult to replace - one bolt each.