2001 silverado 4.3-v6 miss fire

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

Here's a link to the P0300 code,

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

About the possible solutions, try...
* 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.

Keep us updated.

Code p0300 is multi- misfires [ any number of the cyinders ]. Sometimes when a fuel pump is replaced, the system will have air inside and will mis & backfire untill the air is cleared back thru the return line, or blead out the test port. This will set the p0300 code. It's rare to have a backfire bad enough to have an explosion, bleed the lines thru the test port untill you see no more bubbles comming out.

Check engine light on? Any codes? Missed before and after the cap was changed? Or is the cap new so you assume its good. I have had caps bad out of the box.

http://groups.yahoo.com/group/villagerquest/

all trouble codes you have are miss fire codes p0304 #4 cyl p0306 #6 cyl p0300 random miss fire sounds like you may have bad spark plugs,wires,or coils

if you haven't try getting new dis cap and coil wont hurt to replace anyways and a plug wire will arc off other plug wires and cause miss fire may try replacing wires as well.Hope this helps, Good luck

P0300 indicates that there is multiple miss fire in the ignition system. P0303 and p0304 indicates the miss fire is in cylinder #3 and #4. Replace the spark plug, and wire set, and rotor and cap if there is one. Can not remember if there are coil packs on the civic, the age thing. change the fuel filter and clean out the fuel injectors with fuel injector cleaner for the next 3 full ups. When the spark plugs are removed, inspect them for condition, if there clean or dirty with carbon build up. which would indicate how the engine is running. Keep me posted and drive safe.

Check the fuel regulator. Pull the vacuume line. If fuel comes out, it's bad.
Another thing to check are your plug wires. When its dark, Start the engine, put on the A/C, radio, headlights, anything to put a load on the motor, and go to the engine compartment and look for cross firing on the plug wires.