4.2 Vortec motor getting error code P300

[MOMO]

2006 Trailblazer LS
4.2
Somtimes the Engine check light is on.
the dealer replaced the CAM sensor & reset this alarm & latter came agin

question = somtimes I get the engine check light on & every time when I ask the Chevy they are saying its the quality of the petrol u are using,but actually I'm filling with the best quality in my city.& they are saying the engine is reporting engine missfire alarm & thats why the light comes on,please your help.

[TerryAuto]

Fuel guality should have nothing to do with a cam sensor code, but can cause a misfire code.
Depending on the cam sensor code, you may have a faulty exhaust camshaft actuator solenoid.
This part is part of the variable cam timing system.
They can leak oil into the electrical connector, or the screens on the inside of the solenoid.
It is located on the passenger side of the front of the engine, just below the valve cover, near the power steering pump.

[JoeB]

I have a 2007 trailblazer with a 4.2 vortec motor with 4 wheel drive. I am getting a funny noise from the motor and the engine light came on. I had the codes read and it came up with a P300. Can anyone give me any suggestions on what this can be.

[wildman]

Here is the site link for engine codes :: https://www.greatautohelp.com/dtc/pcmdtc.html

300 on the list is engine misfire.

With a "funny noise" coming from it, could you describe it in more detail.
Like, does it sound like it's missing, whining noise, clicking, chirping, or etc.

The cause might be anything from dirty fuel injectors, a vacuum leak, low fuel pressure, a weak ignition coil, bad plug wires, or compression problems. Saw once or twice a broken distributor cap cause it. Even more serious would be worn timing.

That's why I'm interested in what type of noise you have

[Udey]

I'm getting a misfire on cylinder 3 I've changed the spark plugs , changed the coil and the cam sensor and it's still misfiring. Now I'm trying to check the injector but can't figure out how to get to them. I have a 2005 chevy trailblazer lt inline 6.

[ProTech]

The injector rail is right along side the intake manifold. I can tell you this, though, it probably is not a fuel injector problem. The cylinder heads have been known to have issues with the valves which will cause a misfire condition. This will normally require cylinder head replacement or repair and is not an easy job, or cheap either. Before you go assuming it's a bad fuel injector, you should really have it checked out by someone that is familiar with those engines before spending any more money on it.
More on this problem here... Trailblazer cylinder head problem

[Guest]

What would cause my 2002 Chevy trailblazer to cause reduced engine power and check engine light to come on? It also wants to stall out and idle rough especially when AC is on

[carriedi]

you should have your vehicle scanned to see what codes you might have.

One common problem with reduced power showing up is the throttle sensors. When the pairs of throttle sensors don't match up to what the computer wants to see, it doesn't know which set is correct so it will default to reduced power mode.

with the throttle by wire systems some throttles don't have and Idle air control anymore. they use the throttle to control the air to keep your engine running at idle. So if you have a problem with your electronic throttle it will affect your idling as well as your driveability.