In one of my previous threads, I mentioned that I had a lean mixture problem (codes P0171/0174. I took it to the dealership and they performed a smoke test..no leaks. I wrote back to this forum informing you of the situation...and you said, that test was NOT enough and that I would get the engine light back on. Sure enough, engine light came back on..same codes as above BUT THIS TIME, I TOOK BRUTUS'S ADVICE and informed the dealership to review the BRAKE BOOSTER PIPE SEAL DOWNSTREAM FROM THE EGR. Dealership took the advice and BRUTUS WAS RIGHT..several seals NEED REPLACING.

Thank you BRUTUS and Jagular for your advice and support.