2003 explorer sport trac help

[bigdaddybiker61]

I have a 2003 explorer sport trac.Rough idle,have changed plugs,wires,coil pack,cam position sensor,pcv valve,pcv hose,no vacuum leaks,check engine light flashes between idle and 1500 rpms,goes solid after you get up to road speeds,back to flashing when you come to a stop.Has codes po 172,po174,po300,301,302.303.316.Any ideas?

 

[Big_Pezzy]

Fuel delivery problem? Not an expert or anything, just speculating and hopefully this reply will bump your thread so someone smarter than me can chime in.

An entire bank is misfiring, One bank is rich while the other is lean, and misfire on start up
That's crazy.

 

[TJ Sport]

I had a rough idle and intermittent bucking on my 2003 Sport Trac. OBD showed codes for misfire at startup and idle. Finally, I heard a lot of noise under the left valve cover. Found the chain guide for the cam chain had come apart and the chain was flailing around. I just installed the new cam chain and guide today. Also found the guide for the jackshaft chain is chewed up. Turns out, someone installed the crankshaft sprocket backwards. I'll be pulling that and turning it around, installing the main timing chain, and timing everything tomorrow.