[jellajello]

Hi everyone!
New to the forum but I'm hoping to maybe get some advice/help on an issue I'm having with my 2016 Camaro 3.6L V6. When I get out of work everyday and my car has been sitting in the Texas heat for 8 hours, it starts right up but as its warming up and above 1k rpm, the tach bounces a bit (maybe by a couple hundred rpms, like between 1.1k and 1.3k but bounces between them) and the sound of the rpms bouncing is noticeable. Once it goes back below 1k rpm, the tach no longer bounces and the car runs fine, no rough idle at all. Also, I have no engine codes whatsoever. I have an OBD2 code reader that also shows me live data and I noticed that my long term fuel trims (LTFTs), especially in only one bank, was around 12. Now my car has 90k miles on it so high LTFTs aren't suprising, but thats a little concerning. Cleaned the MAF sensor just in case also but that didn't seem to make the problem go away. I do have a cold air intake from Cold Air Inductions, which I installed in January, and this issue just started happening so I doubt the intake has anything to do with it, but it has been on my mind. Anyway, I took it to my local chevrolet service department and they found out my intake manifold gasket was bad, and while they replaced that, I let them replace spark plugs, fuel injector cleaning, and throttle body cleaning. They guaranteed me that there weren't any vaccuum leaks besides the intake manifold gasket, and they told me that an LTFT value of 12 isn't necessarily a bad thing. And after all that, it still didn't fix the weird startup tach bouncing issue. At this point I'm just chalking it up to the heat and hoping that it goes away when the weather cools down. It doesn't do it if the car is in the shade or in the morning when it's cool outside, that's why I'm thinking it's just the heat.

If anyone has any more advice about this issue please let me know, also if this is normal or not!

[Gen6cyl]

I keep engine cover off to keep bay a little cooler. My tach quit once.I did a net search, pushed fuses in at under hood box. That fixed it.

[Keko]

Since you cleaned the MAF it might be worth unplugging the battery for 10 mins so the fuel trim data can reset and learn from scratch. Also helps trims after the intake install (if it wasn't done at the time).

[jellajello]

Originally Posted by Keko

Since you cleaned the MAF it might be worth unplugging the battery for 10 mins so the fuel trim data can reset and learn from scratch. Also helps trims after the intake install (if it wasn't done at the time).

I disconnected the battery on both occasions, when I cleaned the MAF and when I installed the intake, and I'm sure when the service department replaced the intake manifold gasket, spark plugs, and cleaned the fuel injectors and throttle body they disconnected it. I remember after I cleaned the MAF and diconnected/reconnected the battery that it seemed to not have the tach bouncing issue for a couple days, but it did come back. I can always disconnect it again though just to see what happens lol

[jellajello]

Originally Posted by Gen6cyl

I keep engine cover off to keep bay a little cooler. My tach quit once.I did a net search, pushed fuses in at under hood box. That fixed it.

I'll try that, thanks!