I have a 2007 SS 2.4 N/A with 57000 miles.
Over the past few months, my mpg has dropped off to about 19 and I have a significant loss in horsepower. My 0-60 time is up to about 8.8s from the previous mid 7s! It feels kind of dead off the line and dead again between 3k-4k rpm. Also, when I stop a bit hard or sometimes just stop regular, my rpms will jump to about 2k while sitting still then they will slowly tick down back to idle.

So far, I have done the throttle body cleaner and it is not throwing any codes. I know there is an issue though because this car is so slow all of a sudden and terrible MPG.

Any suggestions?

 

are you sure your times are that slow? I assume you are just using a phone or watch to time it. Maybe try an oil change, spark plugs, thermostat, fuel filter, seafoam it.

 

when was the last time you changed your air filter?

 

Fresh oil, k&n filter about 10k ago. Haven't done plugs, only has 57,000 miles. I am sure of those times

 

Clean the filter, change the plugs. You should be cleaning your filter or replacing it every oil change (4,5k miles ) .

 

Also clean your maf and use mid grade or premium fuel (iirc the 2.4l do better on higher octane fuels, there is a thread around here somewhere)

 

******* forced induction install

/thread

 

but really

Basic maintenance ****
Dont seafoam...that ish dont work Find a shop that uses BG products and have them do an air induction service...The shop SHOULD have the proper container that they dump the can into it, hook it up to manifold vacuum and let it do its job. The BG 44K is a fantastic cleaner that you can dump into the tank and it will help to minimize the amount of carbon buildup

 

could also be the water pump valve being stuck open. Common failure in the LE5.