CEL, I/M status, and drive cycles.

[Cobrajet]

I've been trying to clear my recurring check engine light P0405/P1404 for the last nine months. I installed a new NAPA EGR valve last October, and the CEL went away. It came back with a vengeance returning from Georgia after Christmas. I thought I may just have an electrical problem, so I installed a new battery, replaced the positive battery terminal, and re-installed my OEM EGR valve. THE CEL light eventually went away after a trip to Pennsylvania in February, but returned a few weeks later. I started monitoring the codes returned over the next few months. Swapping the OEM and NAPA EGR valves. The OEM gave P1404 consistently with P0405 most times, while the NAPA always gave a P0405 code.

A couple weeks ago I started reading about "drive cycle" because a test of my I/M sensors indicated a "Not Ready" state for the Evap System and HO2 Sensor. I performed the drive cycle steps (warm up at idle, drive a few miles through town with headlights/mirror heaters on [battery load], drive at least 5 miles steady at 55-60 and then coast to a stop, and finally drive a few miles around town***) and ALL systems and sensors returned a "Ready" state. However, shortly after resetting the codes (~30 seconds) the CEL comes back on and the Evap and HO2 sensors report "Not Ready". I've done the same drive cycle in the past two weeks, once with each EGR, and the results are the same.

I believe I may have solved the OEM code P1404 today when I noticed that the pintle was sticking very slightly in the closed position on a small ridge of carbon. Cleaned off the carbon, and sprayed the EGR with carb cleaner. No more P1404 code.

My question to anyone with a scanner that can read the I/M Ready status, is if the Evap and HO2 "Not Ready" status is normal during a non-drive cycle scenario, and if there is a certain number of drive cycles required to PERMANENTLY clear the P0405 code. It's driving me crazy!!

*** I forgot to mention that the Evap test requires that the tank be between 1/4 and 3/4 full. I will maintain this range unless I go on a road trip.