So I have been racking my brain and researching like a mad man trying to find out why my car suddenly started running crazy rich above 4 psi. I ran across stuff about pcv valves and I am thinking this is maybe causing it. Maybe it is stuck open. Anyone heard of this? Here is some info I found which makes me lean towards this conclusion.

The PCV Valve
The most critical part in the PCV system is the flow control valve, commonly
referred to as the PCV valve. The purpose of the PCV valve is to meter the flow
of the vapor from the crankcase to the intake manifold. This is necessary in order
to provide proper ventilation for the crankcase, while not upsetting the fuel/air
mixture for combustion.
Blow-by gases and vapor should be removed at about the same rate they enter
the crankcase. Since blow-by is minimal at idle and increases during high speed
operation, the PCV valve must control the flow of vapor accordingly. The PCV
valve is designed to compensate for the engine ventilation needs at varying
engine speeds. It is operated by manifold vacuum which increases or decreases
as engine speeds change.
For example, at low or idle engine speeds manifold vacuum is high. This pulls the
plunger to the extreme forward position, or manifold end of the valve. Due to the
shape of the plunger, vapor flow is reduced to a minimum. The low rate of the
flow is adequate for ventilation purposes and will not upset the fuel/air mixture
ratio.
At high speeds manifold vacuum is decreased. The plunger is only drawn to a
point about midway in the housing. This allows a maximum flow of vapor. Since
the engine needs more fuel/air mixture at high speeds, the introduction of more
vapor does not affect performance. In the event of a backfire, pressure from the
intake manifold forces the plunger to the closed or engine-off position. This
prevents the backfire flame from reaching the crankcase and exploding the
combustible vapor.
A neglected PCV system will soon fail to function and the result can be
expensive as well as troublesome for the car owner. If the crankcase is not
adequately ventilated, the motor oil will quickly become contaminated and heavy
sludge accumulations will begin to form. Internal parts, not protected by the
motor oil, will begin to rust and/or corrode due to the water and acids that will
become trapped within the crankcase. If the PCV system is not functioning
properly, the flow of crankcase vapor into the intake manifold will not be properly
metered.
This, in turn, will upset the fuel/air mixture for combustion and cause rough idling
or even stalling of the engine. Furthermore, intake and exhaust valves, in
addition to spark plugs, may well be burned and rendered useless, prematurely
affecting performance and requiring expensive repairs. To assure trouble-free
performance of the PCV system and, in turn, the engine and vehicle, routine
maintenance of the PCV system is absolutely recommended and required.
A PCV valve should never be cleaned and placed back into service. Cleaning a
PCV valve will result in a clean PCV valve; not a new PCV valve. There are
contaminants that will remain in the PCV valve that can never be flushed out.
Additionally, there is an amount of wear that will be experienced by the spring
that cleaning cannot replace. The recommended replacement intervals are a
maximum of 12 months or 10,000 miles (16,000 km). Since vehicles and
operating conditions vary, the valve may have to be serviced more frequently. If it
is suspected that the valve is sticking or if there is evidence of sludge, the valve
should be replaced.
All hoses or tubes used in the PCV system should be cleaned and inspected. If
any cracks or breaks are noticed in the hose, it should also be replaced. All hose
connections should be inspected to assure an air-tight seal.
Proper servicing of the PCV valve system will help reduce overall vehicle
emissions.

 

Do you have Utec? If the weather gets warmer and if you Temp Correction isn't setup right then you will get a richer A/F.

 

are you running the pcv system per the vortech installation instructions? since you are FI now part of the operation above is right and some is not true due to positive pressure/ boost in the intake manifold when the BPV is closed during partial or full throttle operation. i do not run my pcv system per the vortech installation instructions. reason being is if the pcv valve sticks open during boost conditions you will actually be pressurizing the crankcase during boost conditions which can actually force the oil/vapor out of the engine and into the inlet side of the blower via the line that goes from the back of the left hand valve cover to the fitting on the aircleaner or i have also seen on some engines the oil dipstick pop out due to excessive crankcase gases. excessive crankcase gases could cause a richer A/F condition and also increase the chances of detonation due the oil vapor cuts down the octane rating of the fuel. are you running a catch can? quick thing to check is get under your car and check the outlet of your BPV if there is a heavy build up of oil in there further investigation will be needed. let me know what you find.