I picked up an 05 Navigator with the 5.4L. It has 180k miles which is high but I got it for a very good price. I had a 2004 Navigator that I loved and this is replacing that truck. It ran similar to this one when I bought it too... (I like buying mechanic specials). The 2004 had a clogged cat which took a bit to figure out but ran like a dream once unclogged.... until it got totalled.

So with this 2005.... I need some help

Not clogged cats... checked already
Fuel Injectors ticking normally under stethoscope (although did not verify fuel rate of each).
New COP on all 8 cylinders
Tested Ignition Harness for proper signals to coils
Was hoping spark plugs were bad but while I tried changing them I kept pulling out near brand new plugs... person before me must have thought the same thing I did and sold it because they found something major wrong with it. (I bought at an auction)

The only codes it threw were for cylinders 1,2,3,4 misfire. No other codes. The passenger side cat is cool enough to touch when it runs.


I know it's a variable timing engine. But I was told if that solenoid goes bad it would through codes for it. So I'm kind of stumped... anyone lead me in the right direction I would totally appreciate it.

 

vacuum leak . fuel filter

 

Checked for vacuum leaks but don't know if I'm missing anything. I pulled the injectors. Put them on a flow bench.. all within 1-2% of each other lol... damn

Couldn't find a shrader valve in the engine bay on the fuel rail to test the pressure but since it seems to run bad on the passenger's side it wouldn't explain the lope sided performance of the engine.

I think it's either with the cam or the compression on the cylinder. The compression tester that I had didn't fit the spark plug sockets on this truck. Time to sell it for what I paid for it or swap the motor out.

 

It could be the boots on the coils. Check the fuel injector harness for any chafing or insulation rubbed thru. You could even run an ohms test on each wire of the harness to make sure it's good. Did you check the fuel pump and fuel pump control module and all connectors? Are all connectors good? If you have access to and Powertrain and Emission Control manual, you can diagnose by symptom. It's bailed me out more than once using that manual.