Lunging issue while accelerating - Question about coil packs and dirty

Kerrslight · December 7, 2015

So had this issue for a long time now and never really got around to try to do anything about it until now. Going to do my best in trying to explain what is going on.

So since I got my truck, as we all have probably experienced, it had pretty sloppy shifting, etc. One of the things in particular that annoyed me was this surge/lunging feeling as I accelerated in 1st gear. Basically if I was on the gas any harder than very lightly the truck would accelerate and somewhere around 2000-2100RPM the truck would kind of surge/lunge forward like I just pressed the gas down harder, then continue to operate normally after that. It is nothing drastic, but its an accurate statement to say this truck doesn't accelerate smoothly from a stop. In addition to that, if I get on the gas hard from a stop, the truck powers up hard and strong up until 3/4 through the gear, plateaus for a second, then gets back on it hard again. Meanwhile my foot has never left the floor. Lastly, lets say I'm just cruising down the highway and decide to get on it, occasionally if I floor it, sometimes the truck hesitates, then runs like a bat out of hell. Best way for me to describe this part is it almost feels like when I stomp the gas, it chokes, then takes off.

Fast forward. I get a Diablosport i2 and use a canned tune for a while. Really was a huge improvement over stock, but my one real complaint was really the surge issue in 1st gear. At that point I thought it was something the canned tune couldn't override so I got a Diablew tune and man was that light years better than the canned tune. Also it did help my issue, but it is still there. Talking with Lew about this, he said he's never heard of an issue like this with the new trucks and nothing he can do about it. He did some research for me and said he found someone with a similar issue. Said some have replaced coil packs and that solved a problem, had their injectors all gunked up and needed to be cleaned, even bad spark plugs. I'm aware of the oil that goes in through the intake with these DI engines and have yet to get a catch can, but has anyone seen or heard of any symptoms like this before? I don't know much about the coils or how to go about cleaning the injectors. I'm getting close to running out of mileage under warranty so I'd like to get this looked at relatively soon. I just like to go in with a good explanation of what is going on and something damn near close to a solution to hopefully point them in the right direction. That has been a good method of solving my problems with the dealership.

Any help is very appreciated on this. Thanks guys.

HondaHawkGT · December 8, 2015

When it comes to injector cleaner, the best option is a PEA-based product like Chevron Techron or Gumout Regane All-in-One. Some guys will jump in at this point and say that it's a waste of money and that as long as you buy Top Tier gasoline, there are plenty of detergents already. I think that with oil prices beeing so low and oil companies being pressured to cut costs, fuel quality has dropped a bit. I watched a recent news report where they sampled the detergent levels from several different gas stations, all supposedly "Top Tier". The range of detergent levels was huge. The minimum levels required for TT gas was surprisingly low. Most stations were just over the minimum required and a few like Chevron had quite a bit more.

Another product I use just before oil changes is CRC's GDI IVD. It's an aerosol form of valve and combustion chamber cleaner with a highly concentrated form of PEA. The difference it made was beyond what I had expected.

You should definitely look into checking the coil packs and spark plugs too. Keep in mind that the Diablo Tuner can void your warranty if the dealer or GM finds eviidence of it. Not going to get in a debate over tuning and I don't think your tuner had anything to do with it. I've suspected an intermittent isssue with a coil pack or injector on mine too. It's most notable at 3/4+ throttle as the truck approaches the 3-to-4 shift point. The CRC cleared most of it but I think there's more going on.

Kerrslight · December 9, 2015

When it comes to injector cleaner, the best option is a PEA-based product like Chevron Techron or Gumout Regane All-in-One. Some guys will jump in at this point and say that it's a waste of money and that as long as you buy Top Tier gasoline, there are plenty of detergents already. I think that with oil prices beeing so low and oil companies being pressured to cut costs, fuel quality has dropped a bit. I watched a recent news report where they sampled the detergent levels from several different gas stations, all supposedly "Top Tier". The range of detergent levels was huge. The minimum levels required for TT gas was surprisingly low. Most stations were just over the minimum required and a few like Chevron had quite a bit more.

Another product I use just before oil changes is CRC's GDI IVD. It's an aerosol form of valve and combustion chamber cleaner with a highly concentrated form of PEA. The difference it made was beyond what I had expected.

You should definitely look into checking the coil packs and spark plugs too. Keep in mind that the Diablo Tuner can void your warranty if the dealer or GM finds eviidence of it. Not going to get in a debate over tuning and I don't think your tuner had anything to do with it. I've suspected an intermittent isssue with a coil pack or injector on mine too. It's most notable at 3/4+ throttle as the truck approaches the 3-to-4 shift point. The CRC cleared most of it but I think there's more going on.

Thanks for that info. Going back to the CRC, where can I get some of that and how is it applied? If its relatively cheap and easy to use, I'll probably give it a shot. Also this may be a goofy question, but how do I go about checking/replacing the coil packs?

YQatari · December 9, 2015

Mine did the same even with black bear tune, Whipple supercharger solved it haha!

Kerrslight · December 9, 2015

Mine did the same even with black bear tune, Whipple supercharger solved it haha!

Lets get a video!

fondupot · December 9, 2015

I think my truck does what you are saying too. Always assumed it was the transmission.

Kerrslight · December 10, 2015

I think my truck does what you are saying too. Always assumed it was the transmission.

For all I know everything is normal. Just feels kinda goofy to me

scott19677 · December 10, 2015

For all I know everything is normal. Just feels kinda goofy to me

"If I had a nickel" haha

fondupot · January 14, 2016

For all I know everything is normal. Just feels kinda goofy to me

Any update on this? Have you done anything to your truck?

I have been thinking about checking my spark plugs. I am coming up on 30,000 miles. Figured it couldn't hurt.

Kerrslight · January 14, 2016

Any update on this? Have you done anything to your truck?

I have been thinking about checking my spark plugs. I am coming up on 30,000 miles. Figured it couldn't hurt.

What part of this issue do you think your experiencing? The lunging or the plateau feeling when your accelerating? I really don't notice the lunging anymore. I think I was just being too sensitive on that and if it does still do it, its not noticeable enough for me to worry about it. The plateau while accelerating feeling, really does bug me though.

No I haven't tried taking it to the dealer yet. One of these weekends I'm not busy I'm going to tune truck back to stock and see if I get the same response when driving. I highly doubt it's tune related, but just want to prove it. Beyond that, I will check all of my plugs. I've had luck in the past using a copper wire bristled brush and cleaning plugs and had a positive response. Beyond that, the only thing I could think of is its just the way these new DI engines perform.

fondupot · January 14, 2016

I've experienced both what you just described.

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Kerrslight · January 14, 2016

Well if you end up digging into your truck and find any results before I can get my hands on mine let me know. I'll do the same for you.

fondupot · January 15, 2016

Well if you end up digging into your truck and find any results before I can get my hands on mine let me know. I'll do the same for you.

I did a little test this morning driving in D vs M6.

For whatever reason, the truck doesn't lunge in M6. But in D it does. Granted, its not every time. But it's more often than not. I need to email Blackbear to see if they know what the different parameters are between M6 and D on the transmission tuning.

Kerrslight · January 15, 2016

I did a little test this morning driving in D vs M6.

For whatever reason, the truck doesn't lunge in M6. But in D it does. Granted, its not every time. But it's more often than not. I need to email Blackbear to see if they know what the different parameters are between M6 and D on the transmission tuning.

That's interesting. I'll have to try that on mine and see if I get the same results.