I have an 09 GTS. A few weeks ago it starting having problems. When you hit the gas sometimes it would go like normal. Other times it would lag for a few seconds and then go.


Now today I noticed that when sitting still it's idling rough.

It's starts shaking and has a noise under the hood. While shaking and making noise the RPM'S raise. When the RPM'S hit 2 they go back to normal and the shaking and noise stops.

At the bank drive through today it started shaking and making noise. The shaking got BAD. Then it just died.
Luckily it cranked right back up.

It does this rather you are in Park or just in Drive with your foot on the brake.

It does it with and without the a/c on.

What could be happening?

Thanks

 

Is it throwing any Codes? If so, start with that.

If not. Hard to say, could check your spark plugs, clean the MAF.

How many miles are on the car?

 

Could be, idle air control valve, vacuum leak, or throttle positioning sensor

 

Would the throttle sensor make it die completely and then recrank just fine?

My husband seemed to think it was the throttle sensor.

It has 90,000 miles and is still under the aftermarket warranty.
Darn thing was in a wreck AFTER the mechanical problems started. Now I need to get the mechanical fixed so I can leave it at the body shop.

 

Your best bet is to have a scanner ran on the system. Just go to autozone or advance auto, they do it for free. You can have codes presents without having an engine light. Post all codes that are present if any and we can start there.

I can also post how to check the throttle sensor with a multimeter if your husband wants to try that.

 

Simplest things first. Check park plugs/gap.

 

check plugs/wires/vacuum lines for sure.

had a similar problem with my 02, once it was a cracked spark plug wire arcing, and another time i had a cracked vacuum line.