Help! I have a97 E super duty motorhome with the triton v10.
At first i had a bunch of codes saying lean bank1 and lean bank 2, as well the misfire codes on 3,6 and 8.
P171
P174
P303
P306
P308
Changed the COP, same codes.
Changed plugs, same codes.
Changed PCV, same codes.
Changed fuel filter, both O2 sensors, same codes.
Changed DPFS, same codes.
Changed injectors, same codes.
Changed MAS, P171 and P174 went away, started running cinsideribly better. Still missfiring on 3,6 now 7 and 8.
Passed smog tho..


Hooked up vacuume gague to see if possible worn or broken valve springs.
Vacuume shows about 21" at idle, shoots to 0" then 25" and back to 21" when quickly rev'd. Needle vibrates about 1", (21" to 21.5/22").
Ive read this indicates vacuume leak..

I've sprayed starter fluid like crazy on all hoses i can see, no engine speed change..

Any thoughts are appreciated!

 

The DTC's showing lean banks 1&2 tend to begin at the PCV fitting at the bottom back of the throttle body.

DTC's for misfire could be a result of COP boots in back condition, current leaking to the surrounding head. Those might also come from wiring harness connectors to the COP's which is somewhat common in these engines.

You don't mention when/if plugs themselves have been checked or replaced.

IMHO you're spending a lot of money and time on swapping parts not known or proven to be causing your DTC's. Before spending more money chasing what are common and easily solved problems find what's actually causing them.

You can also post these same question in the Modular Motors sub forum for V10's.

HTH

 

The coil on plugs and spark plugs were the some of the first things changed. The wiring harness could be culprit..
Have had two different techs look it over, both have spent full day trying to find an intake leak or short to ground, only to suggest to replace what i have replaced...

 

And the PCV tubing?

The COP connectors are notorious having their locking tabs break away, either from mishandling or age. A good test is with engine running push in and hold the connector to the COP body. If the idle RPM increases or the engine seems to smooth out a bit you've found at least part of that problem.

I replace those parts, others have used cable ties to keep them in full contact with the COP. Having broken a few myself I'm far more careful now removing them. Stubborn ones can be persuaded with a heat gun on low temp and patience.

NAPA EC259 is my preferred replacement, be prepared for sticker shock.

HTH