A Cold engine wastes more fuel the sensors that start the fuel trims are the intake air and the coolant temperature sensor
After the engine warms the coolant and the upper hose thermostat located on top of the water pump starts to open (OE stock) 193 F fully open at 203 F
This also allows warm coolant to flow to the heater hose and circulate the engine block and cylinder heads. After the engine achieves this temperature a change in the fuel system gives in to a mode called closed loop where the fuel is moderated mainly by the O2 sensors and throttle position sensor
The O2s do not control startup or “open loop” fuel trims that is the coolant temp and air intake temp sensors.
A System too rich is either too much fuel or not enough air which is opposite of a lean fuel condition where too much air is present and too little fuel which can be caused by a faulty injector nozzle, pinched fuel line or unmetered air entering the combustion mix and the computer has not calculated the additional air and delivering too little fuel.
In the same, a rich condition components fault can be from poor computer calculations or faulty fuel delivery system , injectors clogged from debris holding them open and dripping fuel or an affected spray pattern not atomizing the fuel efficiently.
If a air intake temp sensor is unjustly reporting the incorrect air temperature or the coolant temperature sensor is reporting a colder than normal coolant temperature this theoretically can cause adjustment issues in the computer’s calculations.
From my past understanding the fuel maps in Chryslers are not retained and adapt with every 50 mile trip.
*(after 2003)
A Leaking injector can sometimes flood a cylinder and wash the cylinder wall of oil by seeping past the piston rings.
If this as you say a consistent issue the oil will start to smell like fuel.
Fuel trims can be monitored by a diagnostic reader that capable of capturing live data they are more expensive than regular OBD2 code readers but you purchase a decent one for under $200 US
A list of fuel banks are listed in the diagnostic software of the reader and it is usually self explanatory after becoming familiar with the systems and their functions most diagnostic software is proprietary but the standards are similar as **all internal combustion vehicles are homogenized by the OBD2 protocols .
practice test information
rich condition
ASE
** after 1996
