Having problems with your Lexus GS 400 ?

I failed the emission test and I also went to get an check engine light test from Auto Zone. I received the codes P0300, P0301, P0302, P0303, P0304 and the results that I received from Auto Zone was valve timimg off, block oil passage, failed oil control valve and electrical circuit fault.

Posted / edited by AnonymousUser on : 20-11-2017

Answers :

All of the codes are from an engine misfire, p0300 is random misfire and p0301 is cylinder 1 misfire p0302 is cylinder 2 misfire etc. check plugs and wires. if problem still persists check for a bad coil. have a good day ! why does auto-zone think this is all of the above. because it is a misfire code. all of above are.
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

Possible Solutions:
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.

Hope helps.
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