ReNissan P0300 Replaced coil packs, OEM plugs, OHM out fuel injectors, No vac leaks, replaced both O2 sensors cleaned MAF sensor verified it is working while engine running Cat's show no temperature differential while running Car runs great cold but still shows pending P0300 code in scanner once heated up car runs horrible throws code

That is a lot of replaced parts! Was this a 'let's try changing this' method of car repair? It doesn't work. A Pro-Grade scan tool computer will usually diagnose the part or the module with the issue. Did you check compression on number 6 for a sticking valve? The other possibility is that your replaced o2 sensor is defective is caused a rich mixture, dumping gas and a carbon fouled plug. Sensors come in qualities at three levels. Always buy the OEM spec sensors as they are so critical to efficient running. Avoid Made in Mexico and Made in China. I recommend Denso.

plugs, wires, coils, low compression, bad pcm, improper fuel pressure, bad fuel, worn out cam, plugged injector, plugged cat, bad O2 sensor, bad MAF, and Vacuum leaks can cause multiple cylinder missfires along with many other things

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code p 0171 refers to system too lean bank1===causes ---intake /exhaust leaks--AIR system---MAF/VAF sensors --fuel pressure/pump--injector/S=== HO2S
code p 0174 refers to system too lean bank 2====causes intake /exhaust leak---fuel pressure/pump---injector/s---AIR system---hose connection/s
the fuel pressure is adequate
The HO2S is the heated oxygen sensor in the exhaust manifold /pipe before the cat converter
( is responsible for the fuel ratio settings )
you may have to pull the injectors to have them cleaned and tested
the maf/vaf sensor may have to be replaced as well

have you cleared the codes between fault reads
clean the maf first .....replace the maf if faulty
coil packs ?
injectors

Try cleaning the injectors with professional type injector cleaning tool and cleaner..

Hi there:P1166 - HO2S11 Heater Circuit Fault (Bank 1 Sensor 1)


P0102 - Mass Air Flow (MAF) Circuit Low Input

A code P0102 may mean that one or more of the following has happened:

• The MAF may be disconnected, or a wiring connection may be bad
• The MAF may be dirty or otherwise contaminated (Note: if you use a reusable oiled air filter, be careful not to apply too much oil or that can contaminate the MAF).
• The MAF sensor may be faulty
• The vehicle computer may be faulty (very rare)

Possible Solutions

The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:

• Verify that the Mass Air Flow Sensor wiring is connected properly and that there are no broken / frayed wires.
• Inspect for any air leaks near the MAF sensor.
• Take the MAF out and clean it using a spray cleaner such as brake cleaner or electrical contact cleaner. Be gentle with the sensor.
• Check the voltage of the MAF sensor (refer to a repair manual for vehicle specific information)
• Replace the MAF sensor.

P1505 - Idle Air Control System At Adaptive Clip


P1507 - Idle Air Control Underspeed Error



P0300 - Random/Multiple Cylinder Misfire Detected
A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.


A code P0300 may mean that one or more of the following has happened:

• Faulty spark plugs or wires
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector(s)
• Burned exhaust valve
• Faulty catalytic converter(s)
• Stuck/blocked EGR valve / passages
• Faulty camshaft position sensor
• Defective computer

• If 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.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.



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The MAF sensor is not the problem, these are cylinder misfires on #1,3 and 4. replace the #4 coil pack, #1 AND 4 use the same coil, replace the spark plugs and the wires.

Try running some fuel injector cleaner through your fuel tank. What you may have are a couple of plugged or missfiring fuel injectors. I would suggest checking all of your wiring to your injectors to insure good connection, replace your fuel filter and check for vacuum leaks.

Faulty coil (pack)

Faulty camshaft position sensor

fuel filter and fuel

the p0300 car's computer has detected that one of the engine's cylinders is not firing p0301 In this case it's cylinder #1.p0302 In this case it's cylinder #2.and so on i would check the three listed above first then check

Faulty spark plugs or wires

Faulty oxygen sensor(s)

Faulty or plugged fuel injector

Burned exhaust valve

Faulty catalytic converter(s)

Stuck/blocked EGR valve

Defective computer Random misfires that jumps around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak that may be a broken hose or in the intake manifold (gasket,spary aruond it with wd40 or starer fluid if the engine idle goes high theres your problem) or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open. hope this helps