Sure you don't have vacuum leak? Will start up fine cold and warm up until going to CL then when O2 doesn't switch the system shows fault. Motor goes to crap at that point. Upstream will show like .1 volt and no switching, stuck on low volts.........I've have them run for a good while (week plus) and never post a light doing that. Will run fine at higher than idle speeds since the leak affects less there.
On both of mine the PCV entry point at manifold was cracked open.
My cars read 18-19% TPS at idle running normally.