Hey folks,

I have a 2005 Trailblazer LT with 124,500 miles. The engine is a Vortec 4200. Had been working great until mid-June. One morning, my wife went to start the vehicle and it just cranked and cranked. I did not hear the fuel pump prime, so I went under the assumption it was a bad pump. I did get it started and out to a repair facility where the fuel pump was replaced. Immediately after that, I had to replace a coil pack on #6, and just decided to replace all of them. Ran fine for a little while.

Fast forward a week or two and the engine is hard to start again. I decided to go ahead and replace the throttle body, so the one of there was dirty. I also have replaced the ignition switch. I'm still having similar issues, where some days it starts right up and runs fine. Other days, it starts, but will stall at idle, and other days, it will not start at all! 

I don't want to get rid of the vehicle as the body is in great shape yet, interior and exterior. When I run a diagnostic on it, the EVAP system does fail, and the catalytic system fails as well. Could a clogged catalytic converter cause some of these issues? I do not have a CEL illuminated and no codes are stored. Used vehicles are a rip-off right now and I feel this vehicle has a lot of life in it yet if I can get this issue isolated. 

THANKS!!!