Alright so I have a 99 B3000 (3.0 V6) that is misfiring with the check engine light on, when I got the code checked it only popped up P0306 upon diagnosing I determined that cylinder 6 is not getting fuel. I already had a new set of plug wires laying around and decided that changing the plugs as well couldn't hurt so I did that along with changing the injector on cylinder 6. After doing so before I put everything back together it appeared as if cylinder 6 was getting fuel. Upon putting everything back together and starting the truck the misfire is still there and it appears that cylinder 6 is indeed not actually getting fuel like I thought it was after the new injector. So I have the truck ripped apart again and OHM checked all of the injectors and they are all reading just about the same value of like 18.5. I switched the plugs on injectors 5 and 6 to check the wiring and see if the problem switched cylinders to make sure wiring wasnt the issue and still no fuel to cylinder 6 with cylinder 5s injector plug on it and cylinder 5 was still getting fuel with cylinder 6s plug on it. I am running out of ideas as to what I can do to determine the issue without just throwing parts at it and hoping something fixes it.

So my question first off is, could low fuel pressure cause only cylinder 6's injector to not fire properly? (I am going to get a fuel pressure tester to check this but havent been able to get to the store yet)

As well any suggestions on anything else to check that could be causing this issue?


Any help is greatly appreciated
-Daniel

 

Welcome to the forum

No, fuel pressure wouldn't cause single cylinder misfire

No probably not the injector, the computer will switch to Batch Fire if it detects a misfire, with a V6 engine Batch fire means that 3 fuel injectors will open instead of just the one like with sequential injection, this is similar to how a carb worked, keeps air:fuel mix available in each side of the lower intake so any cylinder can suck it in when its intake valve opens.
Batch fire was used for many years, switch to sequential injection was done for better MPG

Anyway, easy way to test if a fuel injector is not working is to disable the coil pack for a No Start
Crank COLD engine over a few times and then pull out spark plugs for #5 and #6, in your case, to see if the tips are equally WET with fuel

Next would be compression test
Best to remove all spark plugs and test all cylinders on COLD engine
That way you have an average baseline to compare #6 to

3.0l should run about 160psi static compression

3.0l uses a Waste Spark system which is why coil pack is wired the way it is
1 2 3
5 6 4

1 and 5 fire at the same time so share the one coil in the 3 coil pack
2 and 6 do as well
And 3 and 4 share

So try reversing spark plug wires 2 and 6 on the coil pack, if misfire moves to #2 then coil pack is the issue

 

Yeah I did the unplugging of the coil pack and cracked the engine to check the spark plugs for fuel. 5 was wet every time even with cylinder 6s injector plug on it and 6 had been dry every time with cylinder 5s inector plug on it with both the new injector and the old one.

I am about to head to the store to get a compression tester and a fuel pressure tester just to be sure. Also I tried a completely different coil pack and nothing changed but I will switch the wire location on the coil pack like you said and see if anything changes to be sure.

 

I would pull fuel rail then, #6 passage is blocked