advice please

[DanaSC]

I have a 2012 2lt RS auto. It is under warranty but with a $300 deductible and a 75 min drive to closest place that warranty covers. So I'm not sure if this is covered or what it may even be because if not, I'd rather deal with chevy dealer 5 mins from here. Car came from Carmax.

Ok here's what's going on. Car was perfect. It was jacked up and oil changed Sat morning. Car was fine on a 50 mile round trip Sunday. Monday morning I leave my house and get on road and there's a noise coming from the right front under hood area. It's almost like a roaring sound and it happens as you are on gas increasing speed but you dont hear it while coasting. It's not very loud. You may not even hear it if you're outside of car.

I had a longer trip Monday afternoon, interstate driving. It handled real well doing those 75 mph speeds. No noise. However, when yielding onto the interstate, it had a hard hesitation that was probably going from 2nd to 3rd gear. The hesitation was so harsh it was like you slammed on brakes before it caught itself. Once it got through that, it shifted up fine the rest of the way. If you start from a complete stop, it is fine, but if you aren't stopped, that is what happens. Sorta like approaching a red light and it turns green before you get to it so you just accelerate rather than stop.

So is there a magic button to press to go back to where I was before? lol Anyone experienced anything like this? No engine lights, no codes. It has 61,000 miles.

[1Coopgt]

Check you oil . Just to be safe .

[DanaSC]

Originally Posted by 1Coopgt

Check you oil . Just to be safe .

Check the oil? It was just changed and it's correct level. I wouldn't think it's related to that lol

[LETHAL2SS]

sounds more related to the transmission...

[swampcritter]

Sure you did'nt bend a heat shield when jacking it up?

[DanaSC]

Originally Posted by swampcritter

Sure you did'nt bend a heat shield when jacking it up?

I wasnt here when it was done. My husband and 25 yr old son always changes oils in all of our cars but this was the 1st time they did that one. Is a heat shield around a speed sensor by any chance? I am not familiar with these newer cars. It did have the abs light and traction control symbol light up at crank up one day this week. It went off when the car was cut off and started again.

Edited to add. we just took it for a short drive and my husband can barely hear what I'm complaining about and it shifted smoothly with him. He said they jacked the car up on the other side from where I'm hearing things and he thinks it's something in the wheel. Whatever it is affects shifting though. Not starting from a dead stop though. Like you brake and it downshifts and then you get back on the gas. That's when it delays and hard shifts enough to nearly bump your head on the windshield!

[swampcritter]

No , the heat shield is around the exhaust. I thought it may have gotten hit by the jack and was rattling.A weak battery will cause you to get the 'stabilatrack' light also.Have it checked at just about any auto parts store

[DanaSC]

Could it be bad gas? I had just filled up the night before this started. Only drove it about 4 miles home from gas station. It's one we hardly ever get gas at. Just grasping straws lol

[hunter1660]

If the problem is easy duplicated,did the husband observe it...the harsh gear shift and almost head into windshield?. That would be drivetrain concern and if duplicatible should be covered through warranty.

[DanaSC]

Originally Posted by swampcritter

No , the heat shield is around the exhaust. I thought it may have gotten hit by the jack and was rattling.A weak battery will cause you to get the 'stabilatrack' light also.Have it checked at just about any auto parts store

No its not heat shield rattling. I had to replace one over my starter on my 95. I remember that sound.

[DanaSC]

This thread is pretty much dead on to what I'm talking about. http://www.camaro5.com/forums/showthread.php?t=122674

[HyperV117]

They talk about the throttle control module in that thread. That sort of makes sense as far as the bucking is concerned but I don't see how that would cause the sound you describe. Yours sounds more like a transmission issue. Does the bucking only happen when the car is switching gears?

[DanaSC]

Originally Posted by HyperV117

They talk about the throttle control module in that thread. That sort of makes sense as far as the bucking is concerned but I don't see how that would cause the sound you describe. Yours sounds more like a transmission issue. Does the bucking only happen when the car is switching gears?

Yes just during its shifting. My husband seems to think the sound is unrelated but he barely noticed it.

[christianchevell]

Ever change the trans fluid and filter? roaring could be a exhaust leak, and I would check the usual things check the tightness of the air tube and clean the MAF, check plug wires and hose connections to the engine for PCV and such. But mainly you sound like your getting some slip in one gear. Some performance trans fluid might just get you over that slip, and you might want to check usual problems others have had with a v-6 things; could be from the evaporative charcoal canister to what ever..loose throttle body, bad pedal potentiometer because of DBW...timing etc ....