defaulting to the minds of those most knowledgable..........

continues to set po14 and #3 cyl miss at start up and missfire- been going on for past year - last time cleaned MAF and stayed away for about 200 mi came on then cleared itself - now it's back on

have cleaned tb, MAF and IAC; checked vaccum lines using wd 40 while running to see if note cough or rpm drop; checked torque on intake top lid.
I read a lot about rear of intake vacuum elbow going bad but dont feel anything back there on 4.2. Do hear a vacuum pull "swoosh" from the rear of motor on "tip in" of throttle then goes away. Elbow up front for the "PCV (?) " looks ok.
help would be appreciated

 

Remove and check the vacuum lines on the rear of the engine. Sounds like a vacuum leak back there.