With any performance issue you should always do a diagnostic scan to check for any unresolved fault codes, do a compression test and do a full tune up, start here.
mark (mhpautos)
May 7, 2010 at 5:50 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.