Rep Power: 812

Hey guys, lately I've noticed that when driving normally the engine sounds really loud--almost like I have an intake. Also the tranny seems like it has trouble switching gears (slower). This happens worst when it's cold outside (even if the car is warmed up). Anyone know what's causing this? The sound is not normal. I know cause when it was warmer there was no problem. Is it an air/fuel ratio problem of something else? The only mods I have are K&N drop in filter and grounding kit. Don't know what to do. It feels like the car is struggling, even though it was recently tuned up.

 
Rep Power: 316

Take off the grounding kit. They sometimes cause problems if they are not
connected up right. you have to etch the paint off of where you want to bolt
them up. ALso is your car a Manual or Auto?

 
Rep Power: 812

It's an auto, hence the bad shifting. The engine sounds great in normal warm weather. Just at night when it's cold the noises start.