WORKING ON A 2002 5.9 WITH LEAN BANK 1 CODE. RUNS AND IDLES FINE. LOTS OF BLACK SMOKE SLIGHT ACCEL AND CRUISE. NO APPARENT VACUUM LEAKS AND BOTH O2'S SWITCHING OK. SWAPPED O2 WITH KNOWN GOOD AND SAME RESULT. CLEARED CODE AND RESETS AS SOON AS OBD 2 DRIVE CYCLE COMPLETE. WAS WONDERING IF ANYONE HAS ENCOUNTERED A SIMILAR SITUATION? aLSO, WILL THE VALLEY PAN GASKET CAUSE A SINGLE BANK CONDITION LIKE THIS?
THANX FOR ANY HELP.

 

could be blown pleum causing it , or cracked head