When I bought my jeep it came with the full trail jammer kit TB, module, and intake tube and filter. It was not installed yet. After installation two things happened, one, I notice a big change in throttle response, and the motor ran out better. IE no hesitation anywhere in the rev range. I did not notice any huge difference in power, just smother power delivery. 2 a somewhat loud intake whistle. The K&N setup on my dads chevy does the same thing so I thought it was normal. After a week or so of the whistle noise I got fed up and emailed trailjammer to see if there were alot of other complaints, and if there was a cure. this is the response I got back!
We do have some modifications we can make to the throttle body that should help. With a cold air intake, it will never be as quiet as stock, but it should help. If you are interested in this there is a couple ways we can fix it. The first way is we would issue you a RMA#, and have you send the throttle body to us, and when we receive it we would send you one with the new design. The second way is we can send you one, with a UPS return shipping label to bring the one you currently have back to us, but we would require a credit card to do it this way to insure we get the old one back. As long as we got the old one back we would not charge the card. Either way, we will need your complete physical shipping address to issue the RMA#. Let us know what you would like to do.
1080 South Depot Drive
Ogden, UT 84404
Just to let you know it made a huge difference in the noise department, now I have just a good strong intake sound and no whistle. I don't know if they are still offering this as they were supposed to be retooling all of the new TB they sent out, but it may be worth a try. FYI: all they did was machine a small part of the TPS hole. I saw a picture of it on one of the jeep forums, some guys were doing the mod at home with just a dremel tool.