So I installed a ztube today and noticed my TB was a little dirty. I didn't have TB cleaner at the moment so I drove to autozone with the newly installed ztube and noticed the exhaust note was louder and engine sounded meaner. I loved the way the exhaut note sounded!

After I got to autozone, I took off the ztube and sprayed the TB and wiped it with a rag then put everything back together. When I tried to start the car it stalled but it started on the 2nd try. My car use to idle around 600rpm but it now idles at 800. The car runs real smooth but I noticed after cleaning the TB my exhaust note isn't as loud anymore. I also noticed if I was coming to a stop and put the car in neutral the rpm would go down like normal and then go up a little and then goes back to normal.

The car drives great and idles beautifully. Just the exhaust note is really quiet now and the rpm going up on it's own every time I put the car in neutral. Does anyone know what the issue might be?

 

your car is probably just relearning the idle position. it should get better fairly quickly.

 

I always thought 600rpm idle was too low but it did idle smooth. Is it ok now that the car idles at 800? Also why did the exhaust note get more quiet?

 

my car idles at 800 when i first start it until i take it out of park. roll yours down the driveway or something and put it back in park. it'll probably be at 600.