Something is wrong with no warning lights, please help

[papertowel]

Hey, I’d start by checking a few simple things first. Make sure your spark plugs, coils, and air filter are in good shape since those can affect power a lot, especially on a tuned car. Also check for any boost leaks or vacuum leaks because even a small one can make the car feel slower. If everything looks fine, it’s a good idea to scan for any hidden fault codes that might not trigger the check engine light. Transmission problems are also possible if you notice delayed shifting or slipping while driving. Try sharing more details like how it behaves under acceleration or if there are any unusual sounds, that might help figure it out.

So update, the codes listed above are gone now and have not returned since I cleared them (besides the u0121 but I have had that for almost a year now and it drove fine with it)

Basically the best way I can describe it is it feels like its lazy and that theres not as much torque. The throttle response isn't very good at all, it usally takes a second for it respond to inputs and when it does it just doesnt pull like it did before. Before the throttle was snappy, you would give throttle and the car would feel like it "locked" and it would pull hard, especially at lower rpms. Now it just feels like theres not that there, you give throttle and the car shifts like it should (maybe slower then it should) and then it slowly starts pulling itself forward and you dont get that sensation of torque or power, like all the power isint getting to the ground or as if its being bogged. Seem to improve when the temperature outside is colder but it still persists, its like the car wants to rev but doesnt want to pull when you really have it under load, and the throttle delay is pretty bad usally, enough to where it can cause problems with traffic sometimes.

We just replaced the maf sensor, i fixed a negative ground for the BCM as well.
I have checked the spark plugs and they looked fine for the most part, and they are relatively new. I have also looked at the vvt solenoids and they looked clean, but maybe they aren't running right. The air filter is good i just cleaned it (its k&n) and the oil looks fine, its not overheating, the coolant is good all be it it was lower so I topped it off. The cars making peak boost, and i have scanned the car like 20 times over the past few months and literally nothing other then the codes for communication with the electronic brake module as well as a code relating to the voltage of the sensors in the maf (thats why it was replaced)
And over that time I got zero cels or any lights on the dash so its a complete mystery.

the problems feel more apparent under load or what is would presume is open loop, the car has gotten a little better from the other fixes but its still having this problem and im just stuck as to where to look.

the problems all started about midway through the summer when I began to notice that the car felt weird, it would take longer and longer to shift and they where often rough and harsh and the car just kind of felt lazy and kind of down on power. Towards the end of the summer we ended up doing a trans fluid change and an oil change, the car was at around 125k miles and I have no idea if it had been done before that but the trans fluid looked like it was well overdue for a change. It was dark and smelled bad, If you had asked me i would have had no idea it was supposed to be red, but theres was no debris and it didnt seem absolutely atrocious. We then filled it back up with what we measured we had taken out roughly and then made sure the trans was warm and then checked the drain plug, but whats weird is it seemed like more came out then what should have like it was overfilled before or something, so we put a little bit more in after using the demand plug just to be safe. After that the car definitely shifted better and quicker, but it still felt like it was lacking some power. Jumping to now i am still experiencing that

 

[agaric]

Until you replace the vvt's they are THE unanswered question.
Also, swap the K&N for an OEM filter.
If the K&N was oiled it may have fouled the sensors.

 

[papertowel]

Until you replace the vvt's they are THE unanswered question.
Also, swap the K&N for an OEM filter.
If the K&N was oiled it may have fouled the sensors.

What brands do you guys recommend for the vvt solenoids, i might try that today

 

[agaric]

Best to use what GM was willing to warranty and lasted you this long: oem/ACDelco!