2002 Taurus P1504
I started with P1504, P0401, and replaced the IACV, DPFE sensor, and EGR valve about three weeks ago. Today it started and died, and then wouldn't start and idle. Read out P1504 again. I couldn't get it to maintain idle, drove it on the freeway for twenty minutes, and then the car would idle and didn't show signs of trouble.
IACV is reading good voltage from PCM. Any suggestions?