[infinitereality]

I just put the subject line in quickly with intention to go back and update it..........and forgot. Jerky Transmission would be more accurate.

I've been attempting to find the culprit of this myself with no luck and wanted to see if anyone had any ideas. It's driving me nuts and attempting to solve myself instead of bringing it to the dealership, just a pain for me and then find a car to rent TBD amount of time (aftermarket warranty). I noticed this about 1/4 way in my 800 mile trip home with the car a month ago. It probably did it whole time but first part of the trip was decent bit of traffic. I do believe it's getting worse, I've put about 1500 miles on it since purchase.

I'm really unsure how to explain it, basically there's a jerkiness when driving the car, specifically when trying to maintain a speed and it seems to be getting worse. It's not drastic where it'll jar you, but most definitely know it's doing it. I do know it's definitely powertrain, not suspension. When I'm on the interstate or around town and try to maintain speed, you can feel the car surge or shudder. WOT it runs great. It use to happen up to 1500 rpm, but now it'll do it up to about 2k rpm. I remote start the car in the morning to let it warm up, leave my neighborhood and about 7-8 miles into the drive it becomes very noticeable to me. No CEL ever has come on.

Few things I've looked into:
Car has a K&N CAI on it (was on it when I purchased) so I thought maybe it was a leak after the MAF. I removed and checked thoroughly for any holes or openings in the carbon tube, all looked good. Pulled the MAF and it looked fine, cleaned it with MAF cleaner while I was there. MAF gasket looked fine. All clamps worked properly, but they are regular worm clamps so MAYBE not getting a good seal? Everything is tight and looks fine as far as I can tell. The one thing I did notice is the rubber connector (from MAF tube to carbon tube) is noticeably thinner on the area where it sits on top of what appears to be the AC tubing line, you can see the line in the engine bay picture.

Tried pulling negative cable off and leaving it overnight twice. Upon reconnection, tried the throttle body relearn for kicks with no luck. Added a picture of the TB blade, thought the marks on it are odd looking.

Does the same thing in auto or manual, gear number doesn't seem to matter to it. I can set the cruise control and it seems to partially go away, BUT depends on the speed/RPM though. Throttle pedal related since DBW?

Info about the car:
2018 ZL1, had 4100 miles on it when I purchased. A 70yr old guy owned it since new. He bought and sold it to/from the same Chevy dealership and of course it's also same one that sold it to me. They did their inspection and such, but who really knows what that means.

I've read about the A8 shudder, that issue is how I ended up going down the ZL1 rabbit hole, lol. I just recently found a thread about some A10s being overfilled, fixing to see how to check the level since it sounds like there's no dipstick. I'm at a loss what to check next and would welcome any ideas. Since I'm new to the ZL1 game, I'll attach a few pics of engine bay and while had the CAI apart, maybe something will stand out.

I appreciate any guidance!

[kropscamaro16]

the price of jerky is too damn high!

[FoundNemo]

Try the OEM intake. Report back.

[Jaxcam02]

Originally Posted by FoundNemo

Try the OEM intake. Report back.

this.

[HDRDTD]

Originally Posted by FoundNemo

Try the OEM intake. Report back.

Odds are he doesn't have the OEM intake. He already stated that the intake was on it when he bought the cart.

[Vigilante375]

I'll chime in about checking the fluid level. It's a pain in the ass.

Look at this video and it'll explain it all. Lengthy video but is very informative:

https://youtu.be/dPrP4NQZg6w

[Jaxcam02]

Originally Posted by HDRDTD

Odds are he doesn't have the OEM intake. He already stated that the intake was on it when he bought the cart.

Needs to try and find one unless he can get someone who can take a look at the computer parameters while its running to eliminate the intake as a factor.

[infinitereality]

I knew I'd forget some piece of information, lol. That is correct I do not have the OEM intake unfortunately, so kind of stuck. I was hoping removing and reinstalling the K&N intake that it would have fixed the issue.

When reinstalling the CAI I did notice that on the coupler from TB to carbon elbow, the side for the elbow is larger than I would like. All the other parts fit together as you'd expect, just that coupler on that side seems larger than it should be. Still snugs down fine, but did notice it. They're just average worm clamps would I'm sure doesn't help things. Another things about this CAI is the carbon fiber isn't exactly as rigid as I hoped, I can make it flex by squeezing it although composite ones may do this as well.

I do have a buddy with HPT that should be able to read the parameters, just hard to sit him down to do it. What's the off chance AeroForce interceptor could read the correct parameters? I had to send my old one off to get reflashed to canbus for this car and is currently in route back to me.

Throwing no CEL originally lead me to think CAI is leaking some where.... and hoping that's the case. Just hard to justify buying a used OEM or RF CAI to replace it and may be the issue. I was told when I got the car, the original owner visits the dealership once a week. I'm going to ask the salesman to ask him if he has it still and willing to ship it to me if I pay for shipping. Wouldn't be a bad thing to have in my possession anyways.

I'll watch the video tonight, most definitely not excited to check fluid but I'd be dealership didn't check it when they did their inspection.

I appreciate the help!

[LT4Greg]

I would buy a RF and clean the throttle body blades. Clean the throttle body blades with spray cleaner and reinstall the intake and see if it straightens out. Your blades look like they could use a good cleaning to me. Don’t start the car when cleaning though. Take a rag and clean the blades without the engine running. I have to do this to my 2005 Silverado truck throttle body from time to time and usually the surging stops. Hopefully this will help your ZL1 run better.

[LT4Greg]

And your ZL1 has a A10 auto and not a A8 like the SS has.

[Vigilante375]

Originally Posted by LT4Greg

And your ZL1 has a A10 auto and not a A8 like the SS has.

OP stated that he read about the A8 shudder and knows his car has an A10. Because he read about the A10 being over filled and causing problems.

[Stephen12ZL1]

double check all spark plug connections and possibly replace the plugs. A few guys here have had a bad plug or two causing symptoms similar to what you describe.

[Mark114]

Does it happen with cruise control? With transmission in manual mode? Have you asked the dealership for the service records to see if the previous owner had complained of similar problems? Maybe check the throttle body and throttle cable connectors are clean and tight? Maybe try unplugging devices plugged into the OBD port to see if that changes anything?

[infinitereality]

The TB blades definitely look funky, thought that was weird to look as they do for no reason. Anything in particular to clean them with (or what definitely not to use), that's easy to do and test. Hoping to not buy another CAI, but if I can narrow it down and is the issue I'd definitely do RF vs buying a used OEM.

Didn't think about checking plug wires, another easy thing to check. I don't mind pulling the plugs to look, how bad are they to get to access on the LT4? I've honestly never looked close enough to see.

What parameters am I specifically looking for to see if it is the intake? Ill see if the AeroForce gauge maybe can read them, looks like it'll be back Saturday.

Before I purchased, I did get info from dealership about what they've worked on with the car but no issues. Just did a couple of TSB like the wires, I believe in rear inner fender maybe and 2 oil changes. I did try cruise control in auto, definitely surges less at 70 UNLESS I go under that then it'll surge. Have not tried in manual mode though, but will.

Nothing plugged into OBD2 port, still waiting on my gauge to come back.

If I have a little time before work, I'll check TB connections and plug wires and make sure they're secure and locked. If not will do after work.

I pulled I take off again this evening rotate worm clamps to opposite side and couplers, cleaned MAF again for kicks. No change. It was yesterday when I first removed intake, I do believe it's surging more today than yesterday (and hopefully not just my imagination since I'm paying alot more attention) so that's potentially pointing towards intake.

I did hit up my salesman at dealership, honestly a great guy, to see if he would ask PO if he still had stock intake next time he stops by to visit.

Added a pic of area where coupler doesn't fit as snug as it does on rest if I take. Hard to get a good shot. I may wrap in vulcanized tape over them to make sure it is sealed there, just to test. I think this is a potential spot if air is getting in after the MAF.

This forum is awesome, lots of help and suggestions! Hope to be able to pay it back as the years go by as I learn more about the car. Love this car, even with this issue it's shaping up to be my favorite vehicle I've owned....and not even owned for a month