I'm having a loss of power/loud car issue.1st gear is fine. But from second gear on, specifically from 4500 rpm up to around 7000 rpm the car gets very loud/raspy and acceleration becomes bogged down and laborsome. The sound seems to be coming from the area around the engine. I first thought it was an exhaust leak so I changed all the gaskets. The dealership told me it was the motor mounts but that sounds like an idle issue (and that is when the car runs good) Next visit After I pointed that fact out they said it seemed fine to them and charged me a gain. All I have on my car is an AEM CAI and a catback. It usually happened on hot days when the car ws warmed up but now it's much cooler and it is getting worse. I've looked around on the forum for people with similar issues and have not found anything that fit my situation. I could have missed it but I tried looking. Any help from the community would be greatly appreciated. I live in San Antonio if anyone local has any ideas. Will cook for help...lol

 

Oh Yeah...It's an 04 w/75k miles

 

how old are your ignition coils, spark plugs, and wires?
have you checked the cat?

 

So, you think all those work fine until shifting out of 1st gear?

 

Yes.
could be a bad cat and the issue arises under heavier load. (4500 - 7k rpm)

 

Bad Cat.

 

Agree that it probably is a bad cat.
Since you have an AEM intake, verify that the VFAD nipple behind the throttle body is still capped also.
This could cause a vacuum leak in your intake and do some funny stuff.

 

Wouldn't I get a CEL if the cat was bad? I thought the same thing but the dealership inspected it not too long ago and said it was good. That's what I get for trusting the dealer again...lol I'll check the cat out. I've had a straight pipe before and this sounds even louder when it kicks in and the acceleration really sucks.(once again only at full throttle above 4500 rpm) YI'll check the CAI out also. You all are really awesome. I really apreciate your help and input. I'll have to see if the cat is covered under warranty still...Otherwise.....I'm in trouble

 

when cat is dying (melting inside), you will get serious exhaust blockage and the result would be lack of power after certain RPM. I've been there so I know.

Most dealership these days depend too much on computers. they just plug the WDS in and like "oh the readings are within spec" and will come back and tell you "we inspected it and everything is fine"

 

Cat is covered up to 80k

 

I thought there was a law that required they cover it for 100k since it's a required emissions thing...

 

The law is 80k not 100k. 100k is just our warranty for the engine

 

80k???!!! Sweet...looks like I'm going in this week for a new cat. That's great news! Thanks again people. Amazing how it's gone from engine mounts (dealership diagnosis) to the cat...lol I guess as far as the dealership is concerned it's not rape if you make an appointment....; \

 

just pop off your cat and check it yourself before taking in