Misfires cylinder 6

[RLee276]

I have a 2020 ram 1500 5.7 with 45K MILEs I’m noticing on my scanner mode 6 that I’m getting about. 10 misfires a day on cylinder 6 and 0 on all the rest. NO check engine light annd no codes(except line mismatch and I know that’s because I adjusted my speedometer)and truck starts and idles like it should. the misfires are at low speeds and some times on the highway around 2000–2500 rpm. My fuel air ration is 14.6 and my STFt bouncing around -3 to 7 or 8 and some times bounces to 13–14 but only for a brief second. LTFT is normal between 1 and 3 air fuel command ration is 1
does anyone have an idea what could cause this? I did use royal purple octane boost in a tank of 91 shell fuel and the truck ran great last week. This week after running that fuel down to 1/8 a tank I filled up and tried Lucas octane boost with the same shell 91 fuel.
could the octane boost be an issue or is is something with the tune on my truck? Hemifever custom tuned it for CAI and free flow muffler and it as run great for 3–4 weeks since the tune. .I’m. not getting any check engine lights but I could feel some of the very slight hesitation when I would punch it and I figured it was a misfire. And that’s what let me to check. many help or guidance would be appreciated

 

[HSKR R/T]

I have a 2020 ram 1500 5.7 with 45K MILEs I’m noticing on my scanner mode 6 that I’m getting about. 10 misfires a day on cylinder 6 and 0 on all the rest. NO check engine light annd no codes(except line mismatch and I know that’s because I adjusted my speedometer)and truck starts and idles like it should. the misfires are at low speeds and some times on the highway around 2000–2500 rpm. My fuel air ration is 14.6 and my STFt bouncing around -3 to 7 or 8 and some times bounces to 13–14 but only for a brief second. LTFT is normal between 1 and 3 air fuel command ration is 1
does anyone have an idea what could cause this? I did use royal purple octane boost in a tank of 91 shell fuel and the truck ran great last week. This week after running that fuel down to 1/8 a tank I filled up and tried Lucas octane boost with the same shell 91 fuel.
could the octane boost be an issue or is is something with the tune on my truck? Hemifever custom tuned it for CAI and free flow muffler and it as run great for 3–4 weeks since the tune. .I’m. not getting any check engine lights but I could feel some of the very slight hesitation when I would punch it and I figured it was a misfire. And that’s what let me to check. many help or guidance would be appreciated

If it's something that just started with the tunez that would be my first place I would look. Contact Sean at Hemifever and ask him. Also, why are you wasting your money on octane booster?

 

[Richard320]

The next step to diagnosing it is to switch the plugs with cylinder 4 and the coils with cylinder 8 and see if the misfire follows.

 

[HSKR R/T]

The next step to diagnosing it is to switch the plugs with cylinder 4 and the coils with cylinder 8 and see if the misfire follows.

Correct next step is to contact the tuner since he has a custom tune. It very well could be a tune issue if it just started after installing the tune

 

[Darksteel165]

Correct next step is to contact the tuner since he has a custom tune. It very well could be a tune issue if it just started after installing the tune

Anything is possible, but I wouldn't expect to just be 1 cylinder.
He should NOT be using octane boost... You should be using the same exact grade of fuel if possible.

Why not just run 91 without any boost? I'm not sure I understand what is going on. Just freaking out the system imo.

 

[Richard320]

Correct next step is to contact the tuner since he has a custom tune. It very well could be a tune issue if it just started after installing the tune

As I read it, the truck ran fine after the tune and the problem started on the next tank of gas. In my experience, misfires from bad fuel affect all cylinders equally. Single cylinder misfires have something to do with that cylinder. Swapping coils and plugs is a lot simpler than running an injector balance test or a compression test, so start with the easy one.

 

[Darksteel165]

As I read it, the truck ran fine after the tune and the problem started on the next tank of gas. In my experience, misfires from bad fuel affect all cylinders equally. Single cylinder misfires have something to do with that cylinder. Swapping coils and plugs is a lot simpler than running an injector balance test or a compression test, so start with the easy one.

He is not using the same octane of gas each tank.
He is using octane booster and changed brands too.

I would say go through 2 tanks of the same exact fuel, no octane booster, and on the second tank send the logs to hemifever and have them review and then go from there.

 

[HSKR R/T]

As I read it, the truck ran fine after the tune and the problem started on the next tank of gas. In my experience, misfires from bad fuel affect all cylinders equally. Single cylinder misfires have something to do with that cylinder. Swapping coils and plugs is a lot simpler than running an injector balance test or a compression test, so start with the easy one.

Personally owning a truck with a custom tune by Hemifever, my Dakota, not my Ram, I still say talk to tuner first. He will probably have him do some data logs and can help pinpoint the issue. Swapping coils and injectors is a good troubleshooting technique for misfires, but not the first step I wound take when using a custom tune

 

[RLee276]

Correct next step is to contact the tuner since he has a custom tune. It very well could be a tune issue if it just started after installing the tune

Was about 3 weeks after installing the tune. And truck had ran fine. Not sure if the Lucia octane boost was just a coincidence.
I’ll contact the tuner if it’s not the plugs or coil.
I just finished putting new plugs in cylinder 6 and I’m gonna move the coil as suggested above first.

 

[RLee276]

I wasn’t aware octane boost was a bad idea. But I’ll stay away from it from now on. I’ve only used it twice. And I appreciate everyone’s input.

Let me ask you guys this, I’m at a little over half a tank of fuel. Is it best to run it as low as possible before refueling? I assume diluting if with fresh gas wouldn’t be any help.
And I’ve only been using shell premium for the past month.

When I first got the tune and emailed my logs back Shaun told the truck was running solid and try to stick with what ever gas station I had used because it suited the tune well. And it was shell 91. No additives.

 

[HSKR R/T]

I wasn’t aware octane boost was a bad idea. But I’ll stay away from it from now on. I’ve only used it twice. And I appreciate everyone’s input.

Let me ask you guys this, I’m at a little over half a tank of fuel. Is it best to run it as low as possible before refueling? I assume diluting if with fresh gas wouldn’t be any help.
And I’ve only been using shell premium for the past month.

When I first got the tune and emailed my logs back Shaun told the truck was running solid and try to stick with what ever gas station I had used because it suited the tune well. And it was shell 91. No additives.

So why did you start using octane booster? Which, most of the shelf octane boosters you buy will only raise the octane by tenths of a percentage. So if you filled up with 91, and the bottle says it will increase octane by 3 points you may end up with 91.3 octane. Not even worth the cost of the bottle

 

[Darksteel165]

When I first got the tune and emailed my logs back Shaun told the truck was running solid and try to stick with what ever gas station I had used because it suited the tune well. And it was shell 91. No additives.

^^^^ Go back to just using this.
There is 0 reason to put additives in your fuel assuming you are in the USA.
Any additives you mgiht need are done by the seller (Shell, Mobile, etc).

The only thing you could ever add is a bottle of Heat if you think you have water in your tank and even that would be really rare.

Just run the tank to a quarter or less and fill up as normal and drive it to another quarter, then fill up and test and see if you still get misfires.

 

[RLee276]

So why did you start using octane booster? Which, most of the shelf octane boosters you buy will only raise the octane by tenths of a percentage. So if you filled up with 91, and the bottle says it will increase octane by 3 points you may end up with 91.3 octane. Not even worth the cost of the bottle

The reason behind it is a seen a post on the diablosports forum where people were bragging how much better their trucks run on 93 with a 91 tune and saying some guys were getting better performance that way than with a 93 tune.
I’m in Utah, they don’t sell 93 here. So I tried the octane booster. And trust me, I’ll never use the **** again.

 

[Darksteel165]

The reason behind it is a seen a post on the diablosports forum where people were bragging how much better their trucks run on 93 with a 91 tune and saying some guys were getting better performance that way than with a 93 tune.
I’m in Utah, they don’t sell 93 here. So I tried the octane booster. And trust me, I’ll never use the **** again.

That's not how tunes work.
The tune is "tuned" for the gas you are using.

A 93 tune would work better with 93 gas, a 91 tune on 91...
What a weird brag lol.

 

[HSKR R/T]

The reason behind it is a seen a post on the diablosports forum where people were bragging how much better their trucks run on 93 with a 91 tune and saying some guys were getting better performance that way than with a 93 tune.
I’m in Utah, they don’t sell 93 here. So I tried the octane booster. And trust me, I’ll never use the **** again.

If they are just using the canned tunes that come on Diablo hand helds, I can see why. when I had my 05 Magnum, I'd run he 91 tune with 93 octane and wound tweak the fuel and spark tables. The 93 tunes would cause excessive spark knock and retard timing. When you have a custom tune specifically for your truck, that you have sent the tuner data logs for, you need to stick to the octane it's tuned for.

 

[RLee276]

If they are just using the canned tunes that come on Diablo hand helds, I can see why. when I had my 05 Magnum, I'd run he 91 tune with 93 octane and wound tweak the fuel and spark tables. The 93 tunes would cause excessive spark knock and retard timing. When you have a custom tune specifically for your truck, that you have sent the tuner data logs for, you need to stick to the octane it's tuned for.

I went ahead and contacted Shaun. We’ll see what he says tomorrow. I tried new plugs and still have misfires on cylinder 6. And I’ve noticed today it only does it at idle. Either complete stop or nearly about to stop. 1mph or less.
I put two new plugs in 6. Same thing happened when I start engine and sit I got another miss fire about every 20 -seconds until I start moving. And just then to be sure I moved the plugs from 6 to 4 and swapped coils 6 and 8 and restarted the engine and the mid fire count is still happening all though the they are not happening as fast now. Earlier the count was up to 40 in. 5 mins and right now it’s up to 15 in the same amount of time. Still no check engine light or codes.
I did reset codes the other day and all the emissions checks have not completed. I did read somewhere that a vehicle may run bad til the checks complete.

 

[HSKR R/T]

I went ahead and contacted Shaun. We’ll see what he says tomorrow. I tried new plugs and still have misfires on cylinder 6. And I’ve noticed today it only does it at idle. Either complete stop or nearly about to stop. 1mph or less.
I put two new plugs in 6. Same thing happened when I start engine and sit I got another miss fire about every 20 -seconds until I start moving. And just then to be sure I moved the plugs from 6 to 4 and swapped coils 6 and 8 and restarted the engine and the mid fire count is still happening all though the they are not happening as fast now. Earlier the count was up to 40 in. 5 mins and right now it’s up to 15 in the same amount of time. Still no check engine light or codes.
I did reset codes the other day and all the emissions checks have not completed. I did read somewhere that a vehicle may run bad til the checks complete.

As I tried to say before, it's more than likely a tune issue, or something he could figure out through data logs. Run out the fuel your have now with octane booster in it, and fill back up with just 91. Bonus points if you can find non-ethanol blend.

The fact that it's getting better is probably the adaptives kicking in and adjusting the fuel and spark. Chances are if you cleared the adaptives it would be back to the 30+ count

 

[RLee276]

As I tried to say before, it's more than likely a tune issue, or something he could figure out through data logs. Run out the fuel your have now with octane booster in it, and fill back up with just 91. Bonus points if you can find non-ethanol blend.

The fact that it's getting better is probably the adaptives kicking in and adjusting the fuel and spark. Chances are if you cleared the adaptives it would be back to the 30+ count

I appreciate it man. Thanks everyone that chimed in.