You're probably running the amp'ed outputs into the pre-amp inputs and causing noise enhancement. Try running from the pre-amp out on the hideaway to the pre-amp in on the amp. I had done that at one point and it worked.

 

i actually got ahold of a different dealer and you guys were right. They didnt charge me for the code. Maybe the last guy was blowing smoke up my butt. Anyway, I have the code for the radio after faxing over a copy of the vehicle registration and drivers license. So, tomorrow i am going to hook up the factory headunit and see if the noise is still in the radio.

 

Pretty basic, but I didn't see it mentioned. You should be using resistor spark plugs if you aren't already.

 

Reviving vs starting a new thread as this seemed in line with my issue.

I've had two different aftermarket radios in my 02 SD model - both have engine whine on decel.
I suppose its there on accel but its most noticeable on decel.

I just wanted a current opinion/insight as to whether this thread is/was on track with this issue being related to plugs and wires.

If this is the case - feel free to point me in the right direction for which plugs/wires "should" be used on these trucks.
I'll do some searching on this separately as well.

Thanks in advance.....

Edit - I just found the receipt from the PO and plugs were replaced in April of 2017 with champion double platinum

 

I've had an aftermarket radio for years, installed by a professional shop, the first time they did it they didn't bother grounding the head unit chassis which led to noise and weak signal on AM. Noise was noted on FM but signal OK. I made them ground the chassis properly and those noises went away and AM reception returned to normal... There is a stud on the back of most aftermarket head units which needs a strap connected to a good ground behind the dash.

 

Roger that - I'm familiar but have never had to before so didnt put any thought into that.
I'll begrudgingly take it out again and check it out... LOL

 

The ground is super important and your most likely source of noise. I had noise on one of my installs due to the funky shared ground that rover uses for the (-) on the speaker wiring off the head unit.

Are you using an adapter harness? did you cut and splice into the factory wiring? The rear amp can feed back into the headunit and cause weird noise as well if you are doing funky wiring for that thing to still be used.