Can someone please help me out here.My truck sets a PO300 code which is a randon misfire code.It runs great and idles smooth but I dont understand why it would be setting this code.Its makes no since to me guys.What would cause it to miss some?It obviously is not bad cause I can not even feel it and I can not even hear it at the tail pipes.
Can someone please help me out?Its driving me crazy.
Thanks guys

 

need to get it read with a scanner and it will tell you which cylinder it is

 

Talk to Allen at Nelson Performance, I have had the same code due to modifications, not realy a misfire but Allen can explain it and correct it. allen@ls1truck.com

 

I had the same thing happen on my '98. Check the plugs and wires. Also the poppet valves after the injectors are prone to getting clogged so run some techron through it. That's what fixed mine.
If you have access to a Tech2 or other tool you can pulse the injectors one at time. When I did this, the #1 injector would not "click" because the poppet valve was clogged.

 

When's the last time you installed some new plug wires? The resistance could be off within them...or your cap could be cracked too. Causing an arc to the other terminal.

 

Is that the only code you get?

I had that code along with 'bad egr', 'bad passenger front 02 sensor' and what I did was:

-top engine cleaner
-new front passenger o2 sensor
-cleaned egr

Now I just get the egr code SES lite once in a while so I am going to do a new EGR.

How does the Techron stuff work, I'd like to clean my injectors I have 126K on my 99 L31.

 

A couple bottles of Techron always cleared up my injectors and poppet valves for a few thousand miles. I would say it was second behind the top engine cleaner.