[2023_ZL1-AUTO]

Who's here is running aftermarket coils packs on their builds with +800rwhp, if so, have you had any issues related to the coils?

So, I run the Granatelli Malevolent Coils packs. Twice now in 1 month, I've had P0300 Random Multiple Cylinder Misfire occur. This lights up the check engine light and puts the car in LIMP mode immediately.

The first time it happened, I was rolling a CTSV and it happened at the end of the run. I had a new set of Brisk RR14S plugs with only 2000 miles on them, and Granatelli plug wires. The wires I've had since doing my first bolt on's 7500 miles ago.

After the first P0300 code. I bought a new set of Brisk RR14S plugs and new, but different band of wires. Then, after about 400 miles, the P0300 happened again. This time, I was literally in stop go traffic and was only driving like 5mph.

After asking around and getting so feedback. It's was suggestion that there is nothing wrong with using the stock coils, even on builds with high rwhp. And it would be a good test to reinstall the stock coils and see if the problem happens again.

I've checked connections at the THSPI wiring harness connector to the #7 factory coil pack connector, and all the coils pack wire connectors as well. All seem fine. However, I do have two coil pack wire connectors that have a broken red locking clip that prevents the connector from pulling off. But, they are really on there good and almost can't move since the THPSI port plate/injectors are basically keeping them from moving. So, not sure what else could be the culprit.

Thanks

[LiqTenExp]

Have your reviewed your virtual torque tables and made sure they aren't demanding way more than they should be when you have this issue?

I recently had an issue with this where around 4k rpm every time I'd get a solid MIL and misfire code. I realized a prior change I had made in error buffed my tables up in that area and I had to pull them back down. It was forcing the throttle body wide open in these areas even though throttle position shouldn't have demanded it (that is actually what caught my eye in the log and made me realize my virtual torque tables had a mistake in that area).

If that isn't the issue..................................

I'm on stock coils and plug wires in the 800whp range. The fancier ones shouldn't be worse but feel free to switch back to stock and know they are sufficient to eliminate them. Make sure the contacts wtihin your coil pack connectors don't have broken locks. Take each plug off and make sure that you can't pull the wire out the back of the connector. If you can, you found a problem. I actually had this happen on cylinder #7 on my car. I was chasing plug wires and coil packs and eventually found the harness issue after swapping them around didn't fix it.

What do your knock tables look like?

[Joshinator99]

Originally Posted by LiqTenExp

Have your reviewed your virtual torque tables and made sure they aren't demanding way more than they should be when you have this issue?

I recently had an issue with this where around 4k rpm every time I'd get a solid MIL and misfire code. I realized a prior change I had made in error buffed my tables up in that area and I had to pull them back down. It was forcing the throttle body wide open in these areas even though throttle position shouldn't have demanded it (that is actually what caught my eye in the log and made me realize my virtual torque tables had a mistake in that area).

If that isn't the issue..................................

I'm on stock coils and plug wires in the 800whp range. The fancier ones shouldn't be worse but feel free to switch back to stock and know they are sufficient to eliminate them. Make sure the contacts wtihin your coil pack connectors don't have broken locks. Take each plug off and make sure that you can't pull the wire out the back of the connector. If you can, you found a problem. I actually had this happen on cylinder #7 on my car. I was chasing plug wires and coil packs and eventually found the harness issue after swapping them around didn't fix it.

What do your knock tables look like?

Good stuff @LiqTenExp

Agree that it might be worth putting the stock coils back on and see if the problem disappears.

I’m still running the stock coils at my power level and believe Jason Leiva (@ZL1Atlanta) is as well….

[KingLT1]

Nothing better and more reliable than stock coils. Been this way since the 1997 Gen 3 LS engine debuted... That is when GM switched to coil per cylinder ignition.

[2023_ZL1-AUTO]

Originally Posted by LiqTenExp

Have your reviewed your virtual torque tables and made sure they aren't demanding way more than they should be when you have this issue?

I recently had an issue with this where around 4k rpm every time I'd get a solid MIL and misfire code. I realized a prior change I had made in error buffed my tables up in that area and I had to pull them back down. It was forcing the throttle body wide open in these areas even though throttle position shouldn't have demanded it (that is actually what caught my eye in the log and made me realize my virtual torque tables had a mistake in that area).

If that isn't the issue..................................

I'm on stock coils and plug wires in the 800whp range. The fancier ones shouldn't be worse but feel free to switch back to stock and know they are sufficient to eliminate them. Make sure the contacts wtihin your coil pack connectors don't have broken locks. Take each plug off and make sure that you can't pull the wire out the back of the connector. If you can, you found a problem. I actually had this happen on cylinder #7 on my car. I was chasing plug wires and coil packs and eventually found the harness issue after swapping them around didn't fix it.

What do your knock tables look like?

Great info! I will check/confirm what you mentioned! Thanks

[SOCAL.M6.ZLE]

Hey Scott, I also recall people reporting issues with aftermarket coils "after" I got my MSD's... I only have 6K miles on mine, but you know the cars history, no issues yet... fingers crossed?

[2023_ZL1-AUTO]

Thanks everyone!

Stock coils are going back on the ZL1 !!!! If I have the issue pop-up again I'll update.

I'm basically data log ever drive now, kind of tedious, but I think it's worth it just to see what happens right before the P0300 if it happens again !

[cajunzl1]

What coil pak is your DSX sensor plugged into?

[ZLRob]

Originally Posted by 2023_ZL1-AUTO

Thanks everyone!

Stock coils are going back on the ZL1 !!!! If I have the issue pop-up again I'll update.

I'm basically data log ever drive now, kind of tedious, but I think it's worth it just to see what happens right before the P0300 if it happens again !

No need to do that. Just pull your freeze frame data when the check engine light shows up.

Originally Posted by cajunzl1

What coil pak is your DSX sensor plugged into?

This is why I ran mine off of the evap solenoid instead.

[2023_ZL1-AUTO]

Originally Posted by cajunzl1

What coil pak is your DSX sensor plugged into?

I believe #7 drives side back... I've checked that connection and it seems solid.

[2023_ZL1-AUTO]

Originally Posted by ZLRob

No need to do that. Just pull your freeze frame data when the check engine light shows up.



This is why I ran mine off of the evap solenoid instead.

Hmmmmm....

I'll do the code pull again and see what freeze frame data is.

[2023_ZL1-AUTO]

Originally Posted by ZLRob

No need to do that. Just pull your freeze frame data when the check engine light shows up.

Rob, I have to do that when the check engine light is still on, before clearing the codes ? I found where it was... and there is no data on that tab. Thanks