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The check engine soon light will come on at high speed. code indicates random misfires. had plugs and wires changed. light still appears. light will go off by itself when driving at lower speed

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  • sven1 Nov 12, 2008

    The check engine soon light will come on at high speed. code indicates random misfires. had plugs and wires changed. light still appears. light will go off by itself when driving at lower speed

  • Anonymous Apr 20, 2009

    My 2004 Ford Exployer does the same thing. Misfires/backfires alittle at about 50-60 mph

  • Anonymous Mar 31, 2014

    after changing all the sensors andd catylitic converter and giving it a tune up the check engine light comes on after I drive it a little bit then turn it back on?

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  • 4 Answers

Check the ignition coil.

Posted on Aug 10, 2008

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It reads codes po300 po300 po522 but it runs perfect sometimes I need to press fuel pedal to start?


code p 0300 refers to random/multiple cylinder misfires detected ===causes spark plugs ---HT leads ---injector/s--ignition coil/s---low compression---wiring
code p 0522 refers to engine oil pressure sensor/switch--low voltage ===causes wiring short to ground ---engine oil pressure sensor /switch---ECM
for the first code having to alter the accelerator position ( which tells the ECM to let in more fuel indicates either a low pressure in the fuel manifold or that the injectors need cleaning
At high way speeds when the engine appears to be running good , it is still possible to have random misfires caused by low fuel pressures and /or dirty injector tips
It would be a good idea to check the oil pressure with a mechanical gauge ,then replace the oil pressure sensor/switch

Sep 26, 2015 | Cars & Trucks

2 Answers

Why the loss of power and po300 code?


HARD TO SAY WITH OUT BEING THERE BUT THIS MIGHT HELP .
Crankshaft sensor Was the trouble with my 99 Chevy truck after replacing many components like coil cap rotor wires and so on .
http://www.obd-codes.com/p0102 Code P0300 Causes and Fixes Code p0300 is a code that is generated when your engine has a misfire that is not related to only one cylinder. Sometimes this code will be set in addition to other codes such as p0301 which means that there is a misfire on cylinder 1 (cylinder 1 is the number one cylinder when looking at the firing order. It is generally the forward most cylinder on the engine.). If these engine codes are present as well the you should diagnose those first as they are probably causing code p0300.
This code will set your check engine light and needs to be fixed as soon as possible. If it is not then you will probably need to replace your catalytic converter as well as the problem that is causing your misfire.
There are many causes for this obd code. Since it is a "random misfire" or "multiple misfire" this means that the misfire is on different cylinders and not just one all the time.
Common Causes
  • Low Fuel Pressure
  • Vacuum Leak
  • EGR system malfunction
  • Internal Engine Problems (such as low compression)
Less Common Causes
  • Faulty Coil
  • Faulty Spark Plugs and/or Wires
  • Camshaft or Crankshaft sensors
  • Ignition module
  • Computer

Jun 12, 2014 | 1998 Chevrolet Tahoe

1 Answer

I have a 2004 3.9L Mustang with the "check engine soon" light on. I read the codes and 0300, 0301, 0305 and 0316 were up, while the car was still driving fine. Soon, it started to lose strenght, I bar


Best to read the codes first---code p0300 refers to random multiple cyl-- misfire detected causes-- spark plugs---HT leads--ignition coils--wiring.
code p0301 refers tocylinder 1-- misfire detected causes ---engine mechanical fault---wiring---ignition /fuel system ---injector---ECT/Maf sensor(Mass air flow) ECM.
code p0305 refers to cylinder 5 misfire detected causes ---same as 0301
code p0316 refers to misfire detected during start up -first 1000 rpms---causes--- engine mechanical fault---wiring----ignition/fuel system---injector. I would run a fuel system pressure pressure test as the common causes here is the fuel/injectors

PLEASE RATE THIS REPLY FOR ACCURACY

Mar 24, 2013 | 2004 Ford Mustang

1 Answer

2001 ford taurus 3.0 v6 code p0306 misfire


Please go to this page for engine misfire causes.

Aug 08, 2012 | 1997 Ford Taurus

1 Answer

PO300 code. 3.4L 98 Chevy blazer. (random misfire). this happens at high speeds 16000 rpms and higher. after the engine is warm it is more noticeable and misses at idling speeds. if i take it higher than...


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. it could be any of the following 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
  • also
  • 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.

Jun 08, 2011 | Chevrolet Blazer Cars & Trucks

1 Answer

Hi. I have 1997 mountaineer. The cam shaft and sensor was changed. The check engine light is back on and flashing. The engine idling rough. What could be problem?


THE ENGINE LIGHT FLASHING MAY INDICATE A ENGINE MISFIRE OR RANDOM MISFIRE
Possible causes are plugs/plug wires and or fuel injectors

Mar 31, 2011 | Mercury Mountaineer Cars & Trucks

1 Answer

P0300 Engine Code Ford ZX2 2002 ZTEC dual over head cam engine. Has 107K miles. Has new plugs, Only thing I really notice is when I turn on AC the car seems to stumble at steady speeds, especially...


P0300 Random Misfire

Misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.

A Random Misfire code usually indicates a vacuum leak or bad gas.

NOTE: If a misfire in a specific cylinder should lead you to check the spark plug, fuel injector and compression.

Jul 25, 2009 | 2002 Ford ZX2

1 Answer

Engine light code P0300


I would recommend going back with ac/delco platinum plugs.Some of these "high performance" plugs dont work well in newer gm vehicles.The computer is sensing more than one cylinder misfiring and cant determine the cylinders the style of plug your using could very well be causing this

Sep 03, 2008 | 2001 Chevrolet Corvette

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