Got a p0300 random misfire (pls help if anyone can)

[acespecv]

Hello, new to the forums can anyone help or has anyone had the same prob as me?
ive tested the ecm over and over again, and everyone i talk to says its that and dont think its pos that all three, or two of the coils have gone bad, van did it when it got hot or we thought thats what it was. would drive fine for a few days from first time to second! then a few days later it did it again and now its like whatever was going bad, went bad. because now its doing it right from the start!
its skipping, and lagging! thought the motor went bad but starts fine.
and its off two or more cylinders other then that got a list of things it could be.
but it goes from bad gas, to needing a new motor!!!
Thanks

 

[tomgp]

do you know what cylinders its misfiring ?

 

[acespecv]

sorry no i tryed to check the spark plugs and i think the front middle one wasnt but not sure if i just didnt have it grounded. and it was late and the back three are hard to get to, they were when i changed all the spark plugs about 6 to 8 months ago im about to put the icm back together and try checking all of these, but van sounds really back!

 

[melsg5]

that is a very general code and all you can do is go through each one of the possibilities suggested at this site

http://www.obd-codes.com/p0300

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[tomgp]

with a random misfire it can be lots of things...plugs,wires,injectors,coils,headgasket,ho2s,...if you take it to a dealership they can pull up a misfire gragh on the tech 2 and see what cylinders are misfiring,my shop doesnt charge for that but you can call your local GM shop and see if they do.

 

[acespecv]

Thank yall, im going to start testing the coils and all tomarow, everyone i talked to said u cant test the coils but found out i can!
If anyone has prob here is where u can find out how to test
hope i have some luck, so far haven't been gettin anywhere the cheap way

http://easyautodiagnostics.com/ignition_gm/ign_module_test_1.php

 

[tomgp]

you can also just buy a tester for 10 bucks,it plugs into your spark plug wire and while you turn over the engine it lights up if the coil is working...with a p0300 code 9 times out of 10 it just needs plugs and wires...100k miles is the recommended but i have seen them go bad as few as 40k

 

[acespecv]

Fixed the prob!

I tested, and tested the ICM at parts store and past everytime, and in the end that was the prob! so if anyone has same prob just to let ya know even tho the ICM passes test it still could be the prob!

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[Zimgxp]

Yup, happens more than you would think.