Hello all! I have a 2000 f150 4.2L. So I was changing my wires and spark plugs for a nice holiday tune up and the change went smooth. Drove around felt the pick up. Anyway get back to the house and my buddy decides he wants to rewire the lines and he pulled the spark plug wire off the end of the coil pack without taking the negative terminal off. So i go to start the truck again and its now running rough and misfiring. Any opinions on this?

 

The plug wires aren't connected to the battery, so it doesn't matter if the battery is connected during a wire change. First, make sure they're routed properly. If they are, the wire was probably degrading internally, and he just made it obvious. Read these captions:

 

Once the rough idle and misfire was felt and heard i thought it was the plugs or the wires, thinking that maybe they were shorted. After checking them nothing seemed wrong but i still ran out got brand new plugs and wires put em in and still the same prob persists. So what i scanned the darn thing and got the infamous PO171 and 174 codes. Any opinions on what could cause the Bank 2 lean on this?

 

replace all upper and lower intake gaskets along with the insolator bolts...

 

On the 4.2 the hose for the PCV is right next to the coil pack. You probably accidently knocked it loose or broke the plastic stove pipe. I would start with the PCV system and make sure it is sound. This can give you the lean codes (p0171/174)

The hose/pipe connects to the rocker cover on the passenger side way back by the fire wall. You may have broken the plastic elbow or the rubber hose is burned through.

Also double check that you have the wires correct on the coil pack, it sounds like 2 might have been switched.

 

What I ended up doing was taking it all the way down to the lower intake. This is what I changed.

Isolator bolts
upper/lower gasket
cleaned both upper and lower intake
egr valve/ gasket
cleaned tb/ new gasket
plugs/wires
new coil pack
iac gasket

I went to start the truck this morning it started, no misfiring but rough sounding. So i had my buddy come over this afternoon to run the obd. With the key turned on we didnt get any codes. Went to turn the truck on and it ran for about 15 seconds then cut off. Sounds like a vacuum leak. As far as the pcv valve, i changed that and the grommet and the few little connectors new elbows and what not. Tomo we are going to go over the system again. Any websites with pcv shematic. That whole concomption is ridiculous. Thanks again.

 

Update:

Upon not starting I found that the maf sensor wasnt plugged in all the way. The truck started with no misfiring but has the rough idle still. Took the maf apart and cleaned the darn thing and still the problem persists. Will run obd on truck on weds to find other codes. I have a feeling its either a bad MAF sensor.