help! 04 ST P0175

[Sp0rtTr4c]

Recently my #5 exhaust valve spring broke but the valve never dropped so I just bought a new spring and fixed it. Everything went very smooth except now I have rough idle and throwing p0175 DTC. It is pretty smooth in park and neutral but is rough in d and r. The truck drives fine with no stumbling or surging and never stalls. It has plenty of power and the mpgs seem to be fine. I have no clue what to try at this point. Below is everything replaced including fixing the valve spring-

Exhaust valve spring
Head gasket
Plastic injector seals
Head bolts
Exhaust manifold gasket
Motorcraft spark plugs
Intake manifold gasket/ orings
Bank 2 precat o2
Pcv valve
New oring on pcv valve to intake mainfold. ( where the 90* hose is)
Thermostat
Thermostat housing and seals
Bank 2 timing chain tensioner
STP air filter
Duralast fuel filter

Parts I have bought that made no difference and that I was able to return-
Auto zone IAC
O Reilly coil

The vehicle is a 2004 explorer sport trac 4.0 sohc with 124,000.

The pcv hoses have all been checked and are fine. Maf has been cleaned. Truck sat for 3 months with half a tank of 87. I have ran 1 tank of 91 through it and am on my 2nd with seafoam added to this tank. Any ideas what the problem could be?

 

[2000StreetRod]

compression test?

P0175 System too Rich (Bank 2)
Running rich is less common than running lean.
What tool did you use to compress the new valve spring to install it?
After replacing the valve spring did you perform a compression test on cylinder 5 and compare the result to at least one other cylinder?

 

[Sp0rtTr4c]

I took the head off and used a special socket and I pulled the keepers with magnet while my dad compressed the spring.

I have not purchased a compression tester but i would assume bad compression would give it a hot start problem.

 

[BustedKnuckles24]

You probably have a different problem unrelated to the valve spring. One or more of the fuel injectors may be leaking causing the code. You could pull the spark plugs after letting the engine cool down a bit after a run and see if any are wet with raw gas.

 

[2000StreetRod]

retime camshafts?

Did you time the camshafts after removing and installing the head?
Did you use the OTC 6488 timing tool kit?

 

[Sp0rtTr4c]

I think it is leaky injector but it is weird that it is only bank 2. Even though I did have those injectors out so maybe something happened to them while they were out.

I did use the OTC kit so the can shouldn't have moved.

The plugs are pregapped at .45 and the truck calls for .54 but once again that should be causing problems on both banks.