dctoner, good luck with the DTT filter. J BODY, thanks for the idea about disconnecting the alternator, I wonder if my serpentine belt would allow me to try that? dansdodgediesel, I will be checking into the alternator brushes. I appreciate all of the ideas that everyone brought up, this is a great forum and a great website.

 

J BODY, sorry about that, don't know why I was thinking you meant taking the alternator off...

 

dctoner, I just talked to my brother who is a mechanic out in rural Missouri. He told me to look in the engine bay and look for connectors in the ground lines. I found a grey connector in the ground that snakes over the alternator; the connector is located by the passenger side battery. I found another grey connector nearby that runs from the passenger side battery's negative terminal to the body. He suggested opening those connectors and cleaning the connections. I will try it tomorrow and see if it helps. He said it seemed to solve the problem on one truck that he worked on.

 

Lumpy_63,

In my description, I included those with my grounds. I actually removed those connections, it is my belief that anytime there is a break in the wire, that is a potential problem.

I put in the DTT noise filter last night so I willl see how it does. I think I had at least minimized the problem before the noise filter because it will only kick out of Cruise instead of kicking out of OD and start hunting.

One other thing that I noticed last night when putting in the noise filter is that the mounting screws that connect into a black painted mounting bracket, then that bracket is screwed into the painted firewall. The instructions for the DTT noise filter wanted me to ground the noise filter to the screw that mounted the PCM to the firewall. I didn't think that this was a good ground, so I grounded it directly to the ground to the body by the air filter. I think I'm going to run another ground from that same post back to the screw that mounts the PCM to the mounting plate to ground the PCM housing.

 

I read a post from a couple of years back where Iwowen used an inductive coil around one of the wires (I think he called it an RF choke), and it cured the problem on a 1998.5. I got thinking about that... I am not very electrically inclined, but I looked back in my old Physics book and it says something to the effect that capacitance dominates at low frequency, and inductance dominates at high frequency. I wonder if that is why in some cases a capacitor helps and in some cases it doesn't? If the problem can be traced to either noise from the APPS or the alternator, it seems like you might need a capacitor to combat the noise from the APPS (which seems like it would be a single "spike" or at least low frequency), but you might need an inductor to combat the noise from the alternator which would be higher frequency. Is there anyone out there that is electrically inclined that could comment on this? Do inductors and capacitors "play together nicely?"