Ruff idol, poor acceleration. EGR light on. Idol was ruff for several days. Replaced distributor,coil,spark plugs,spark plug wires,air filter and fuel filter. EGR light did not come on until after the plugs and fuel filter were put on...on a entirely different day than all the other parts. Runs smoothly with constant acceleration. Please respond at your very earliest covenience. Almost outta patience and money. Rita

P0300 Dodge P0300 Dodge - Cylinder Misfire Fault Detected Random Cylinders Possible causes
- Faulty spark plug (s)
- Faulty ignition coil (s)
- Clogged or faulty fuel injector (s)
- Intake air leak
- Fuel injectors harness is open or shorted
- Fuel Injectors circuit poor electrical connection
- Ignition coils harness is open or shorted
- Ignition coils circuit poor electrical connection
- Insufficient cylinders compression
- Incorrect fuel pressure

Priority Action Part Type Cause
1 Inspect Catalytic Converter Clogged or Faulty Catalytic Converter.
2 Inspect Piston Ring Set Worn or Broken Piston Rings.
3 Inspect Distributor Worn, Damaged or Faulty Distributor.
4 Inspect Distributor cap/rotor Worn, Burned contacts

Priority Action Part Type Cause 1 Inspect EGR Valve Improperly Functioning or Faulty EGR Valve. 2 Inspect Fuel Filter Clogged or Dirty Fuel Filter. 2 Inspect Fuel Injector Dirty or Worn Fuel Injectors. 3 Inspect Radiator Cooling at System Clogged. 4 Inspect Timing Specification Incorrect Ignition Timing. 6 Inspect Coil -Ignition- Faulty Ignition Coil.

depending on mileage, but possible tune-up could fix it. if already done then check ignition coil pack and ignition wires also spark plugs, check vacuum hoses for leaks or porous, last injectors clogged - use some techron fuel injector cleaner (wal-mart has them). Also get the throttle body and iac valve cleaned by throttle cleaner . Also this other possibilities are to be checked and confirmed.:---- Engine running rough or misfiring can be cause by the following:

1.Defective spark plugs
2.Inadequate spark/coil, defective spark plug wire.
3. Lack of compression
4.False air leakage.
5. Faulty fuel injectors.
6. Insufficient fuel pressure.
7. Contaminated fuel.
8. EGR valve that is leaking.
9. Oxygen sensors.
10. Throttle position sensor.
11. Manifold absolute pressure sensor
12.Mass Airflow Sensor
13.Idle air control valve
--------- This should help.Keep updated.Thanks.Helpmech.

New fuel filter? this is the most neglect part of the car. It gets clogged and causes several different symptoms.
Randy

You have a vacuum line off somewhere, or the egr valve is leaking at idol, or you have manifold vacuum hooked up to the egr valve, make sure the vacuum line going to the egr valve has no vacuum at idol, only during acceleration.

I Have a 1999 ford f150 4.6 that back fires and is just running really ruff when idling alot of nack fire a sord of like a pulse going on what is my problem?

A multi misfire may mean that one or more of the following has happened:
Faulty spark plug or wires, Faulty coil (pack), Faulty oxygen sensor(s), Faulty fuel injector(s), Stuck/blocked EGR valve / passages, Faulty camshaft position sensor, Defective computer.

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 wire, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the 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.

Good luck and hope this information helps, keep me posted, be glad to help you get the truck running 100% again. Not sure if your running a K&N air filter, and if you are there may be a flim of oil on the MAF sensor that is making you run lean. You may want to spray down the MAF sensor with a can of MAF cleaner. 

Replace your fuel filter and airfilter. If this doesn't work - you may need a new coil pack or cap and rotor if it has a distributor; if this is the case, change the spark plugs and plug wires.

I have a '94 Altima with 2.4 liter 4 cyl. engine. At around 150K the timing chain and tensioner were replaced - should solve your problem, too. If you're sure the chain is rattling you should really get it serviced now, not later. Also, if your car is running rough it could be more than just the chain and tensioner; it could be your ignition system, such as plugs, coil, distributor, etc. Bottom line is, your car needs to be checked out right away.

Have similar problem, seems to be too much pressure build up in the gas tank, when you loosen the gas cap, there is pressurized air comes out. If I leave the cap loose, the car runs fine