P0301 trouble code will not pass smog test

There are a lot of things that can cause a misfire code. Plugs, wires, and coils are probably the most popular. But you could also be looking at a clogged/sticking fuel injector, a cracked piston (less likely but I have seen it), a leaky intake gasket (even less likely), and a bad PCV valve.

I would look into the fuel injector, myself. Here is a nice how-to guide on checking them: https://www.2carpros.com/articles/how-to-test-a-fuel-injector

If you have not replaced the PCV lately, you might as well go ahead and do it. It wil cost you about $5.00 and take you about two minutes to replace it. Check YouTube for vehicle specific instructions if you cannot see it.

Arghhh! Try this: https://www.2carpros.com/articles/how-to-test-a-fuel-injector

And I definitely understand not wanting to pull the upper intake off just to check a fuel injector. If you're going to try injector cleaner, I suggest the Lucas brand one (available at the local parts store). Put that stuff in with about a 1/2 tank of premium gas (preferably shell or BP, something with a lot of cleaning junk in it). Take that car for a ride, and open the throttle up a few times, without getting a ticket, that is.

If your problem is a sticking or clogged injector, this is probably your best shot at cleaning it out without taking that intake off and replacing it. This has worked for me a couple of times.

It's also a possibility that you've lost some compression in that cylinder. You can get a compression tester from AutoZone or another parts shop and check it against the other cylinders on that bank. Here's another guide: https://www.2carpros.com/articles/how-to-test-engine-compression

Good luck and let us know what you find.

I have never seen anything like that myself. I suspect any product like that would do great at cleaning the rail out, but would not do a bit of good for the injectors themselves.

And honestly, I doubt your problem is a compression related issue. It is possible, but just does not "feel" right to me.

If I can step in and help I would check to see if the coil is getting signal from the PCM I have seen where the coil drive burns out and it does trigger the coil.

Here is a guide check it out and get back to us please.

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Please let us know what happens.

Cheers, Ken

Yeah good thinking Ken. Definitely worth checking.

I'd take a spark tester and just hook it up between the coil and plug wire for each cylinder. Compare the sparks coming out. Here's the spark tester that I use: https://www.amazon.com/Lisle-20610-Inline-Spark-Tester/dp/B0002STSC6/ref=sr_1_1?ie=UTF8&qid=1507690227&sr=8-1&keywords=lisle+spark+tester

They do sell them at the various auto parts stores as well. But Amazon is a little cheaper, as usual. Hope that helps you.

I would do the compression test to make sure we are not chasing a low compression issue on one or more of the cylinders. Can you make short video of the engine running so we can see? Upload it to the site would really help us.

The putt from the exhaust says ignition crossfire or leaky exhaust valve. Are you using OEM ignition parts wires etc?

It may or may not catch a signal error. When a cylinder misfires the voltage to fire the plug is different that's how the computer can tell what cylinder is misfiring. I am wondering if you have a flat cam which can cause the problem as well.

Here is a guide that should shed some light on the situation.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough