Have a 2002 Camaro, 58,000 miles, V6, automatic, T-top, 35 Anivarsary with electronic throttle body. Car hesitates on acelleration, slow in shifting (sometimes must let up on accelerator), looses power. No trouble codes except P0420 [ drop in efficiency on muffler bank 1]. Scanned data while operating seems okay. Have installed new plugs and wires. Replaced (1) injector. Injector system cleaned. replace fuel filter. Fuel pressure hold steady... increases slightly on acceleration on road test. Replaced (1) ignition coil...all three tested resistance wise to be okay. Cleaned ignition module mounting base and new heat-transfering grease. New MAF. Tested MAP with new2 replacement, it is okay. Cleaned throttle body. Visual check of lines did not reveal a leak. Blocked EGR valve with no effect.
HELP!!!!!!!!!!!!!!!!!

 

Possibly the catalytic converter is partially plugged.

 

hey you might wanna check any loose grounds ....trust me.