Intermittent rough engine and misfires both in idle and while driving, codes p0305 and p0300

I might have made a small difference at first but it’s never stopped the issue. I felt a good change after the intake spray at first but has some crazy rough idle and even the oil light came on twice right after I did that treatment. That was befit I did the alternator though and never had the oil light come on again. I did get a p0207 around that time but it was the only time it came on. Honestly the alternator change seemed to have made a big difference when it was done. Didn’t feel like I was gonna be stranded after that but the problem keeps happening.

Hello,

Here is what that code is saying:
What the P0207 code means: The P0207 code is a common OBD2 diagnostic trouble code (DTC) that is set when the Engine Control Module (ECM) detects out of range performance for the cylinder 7 fuel injector circuit. Injector malfunction codes may trigger a lean condition, rich condition, and misfires.

It only popped up once and never popped up again. The most constant codes I’m getting is 300 and 305. Would one injector cause a misfire in another cylinder or a random cylinder?

Also from what I understand, a 305 is not cylinder 5 but the 5th in the firing order. Is that correct? If so from everything I’ve found the firing order is 18436572.
7 and 5 are next to each other on the same bank and firing order but it would be cylinder 6 that’s actually 5th in firing and setting the 305 on the opposite bank.
So if that’s correct and sorry if I’m confused, I’m getting codes on random cylinders and on both banks. I’m open to just getting new injectors, there’s a lot of miles on the truck and not sure if they have ever been done before.

Hi,

I just review the thread at one point you say that the fuel pressure starts to decline soon as it's off, this is a problem. The fuel pressure should stay solid after it's off if it's not the fuel pressure regulator or the pressure gate in the fuel pump is going bad.
Tom

Just put a new pump assembly in a few days ago. The pressure regulator for my Jeep is in the pump assembly itself. Not sure what the pressure gate is but if it’s in the pump I just replaced it. Can injectors cause a pressure issue?

Hi,

Okay, if the pump is new then the gate is fine. This would point to the pressure regulator which is attached to the fuel rail and is run by vacuum. Give me a minute and ill get a diagram of it.
Tom

The diagrams I have say the regulator is inside the Fuel Pump assembly itself. Would there be 2 on a Commander?

There usually is one on the rail. I'll verify that here in a minute. Is this a flex fuel ride?

Yes, it’s Flex Fuel.

Okay, so there is a fuel pump module located on the top of the fuel tank not part of the pump. The module controls the pressure. It's number 3 on this diagram.

I think we should do a leak down test again now that the pump has been replaced. Did you get the pump alone or the whole assembly? I'm leaning towards the module if it wasn't part of the new pump.

I replaced the entire assembly. I’ll see if I can post the part.

That’s a picture of the part. Looks like everything is together in one unit. Filters, pump, regulator and fuel level.

Okay, looks like that's handled. Didn't you say you occasionally smell fuel?

I still think a leak down test should be done again. If it does leak it's the injectors.

Here is a pic of the injector.

1. Remove fuel rail.
2. Disconnect clip(s) that retain fuel injector(s) to fuel rail (2).

The post where I said the fuel pressure was slowly dropping after I turned the key off was after the new pump was put in. And yes I have smelt fuel. My daughter has smelt fuel while riding before but it has been a while and that was before the pump. I had a buddy of mine that helps me with repairs also mention he’s smelt it as well.

I can hook the gauge back up and double check as well. What are your recommendations so that I know I’m doing it correctly?

Okay, that's serious. This is what I need you to do: Run the car a bit pop the hood get a flash light and inspect the injectors at the rail and see if it looks wet. follow the fuel line to the rail and look there as well. If you are smelling fuel like that we need to find it right away. actually you shouldn't drive the car until that's handled.
Let me know what you find there.

So are you smelling the fuel at the front of the car or the middle at the doors more?

Not always smelling it. My daughter was in the back seat when she smelled it but that only happened once. I’ve smelled it up front and also from the back. My buddy was up towards the front. My niece said she smelled like a burnt fuel odor from the exhaust area.

My buddy that helped me do the pump said he did not see any leaks while under the Jeep.

okay, well you are going to need to do a visual inspection of the whole line from the tank to the rail and by the fuel filter. Look for wetness or stains around the line. A leak is going to clean the area it's leaking and the crude will build up and make a stain. How long does it have to run before you smell it?

This leak is going to be the cause of the poor running.
Let me know what you find.
Tom

If I smell it, it’s usually when first starting the vehicle. I had just started up when my buddy mentioned that it smells rich. We were driving for a little bit when my daughter smelled something but it’s also possible she smelled something from outside. The smell from the exhaust yesterday the car had been running almost an hour.

So you thinking it's rich exhaust, un-burned fuel out the tail pipe? if that is the case we are back to the injectors. Next time you start it have someone by the tail pipe and see if they smell it right when it starts.

Have you pulled any plugs during this adventure? if the burn is all messed up the plugs will show it.

So just hooked up the fuel gauge and everything seemed to hold steady.

Key on engine off.

Engine started up and idling, needle shook as rpm was dropping but stayed steady.

After shutting down the engine. And it’s still holding the same pressure a few minutes later.

I have seen video online of and injector failing after it gets hot. Think maybe situation happening here? Seems to always start or get progressively worse with heat.

Just restarted and the fuel pressure went back to right at 58. Although this time when I turned off the fuel pressure is higher than the first time. And holding there now.
It did smell a little rich to me when it was running. Not like raw fuel but definitely can smell something.

Plugs are new. We pulled plugs when we did compression check. They looked okay to me.

There’s some water coming from the tailpipe. I just got it to sputter and held a piece of paper by exhaust. It did suck it in while sputtering.

The pressure from being off should go no lower that 35psi.

The pressure held perfect this time. Is the receipt paper getting sucked into the exhaust a valve issue?

And water coming out the tail pipe is good when you have a good burn it creates water. that is why exhaust systems rust from the inside out. I going with the injectors. I think one or more of them does not have a good spray pattern.
Tom

So no concerns about some suction from the exhaust pipe? It only happened briefly while a sputter was occurring.