P0308 is miss fire on #8
A P0308 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #8.
SymptomsSymptoms may include: the engine may be harder to start
the engine may stumble / stumble, and/or hesitate
other symptoms may also be present
CausesA code P0308 may mean that one or more of the following has happened: Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel
Possible SolutionsIf there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.E. Spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.K.A. Coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Basically this means that an oxygen sensor in bank 2detected a rich condition (too little oxygen in the exhaust). On V6/V8/V10 engines, Bank 2 is the side of the engine that doesn't have cylinder #1.
Note: This DTC is very similar to P0172, and in fact your vehicle may show both codes at the same time.
SymptomsYou will more than likely not notice any drivability problems, although there may be symptoms such as a misfire.
CausesA code P0175 may mean that one or more of the following has happened: The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of " oiled" air filters can cause the MAF to become dirty if the filter is over-oiled
There could be a vacuum leak.
There could be a fuel pressure or delivery problem
Possible SolutionsPossible solutions include: Inspect all vacuum and PCV hoses, replace if necessary
Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect fuel lines for cracks, leaks, or pinches
Check the fuel pressure at the fuel rail
Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)