We had issues with the 4.2 diesels at work causing RFI interference In the 150 - 172 mhz freq's. Your fault sounds similar - uhf CB is at 476 Mhz.
We traced the issue to the ECU, we had some success by warping the ecu in aluminum foil, the problem disappeared with the 3ltd patrols, as they use a different ecu.
If you can get you hands on a hand held uhf cb - turn the hand held on with the squelch open - you should hear hissing. Now turn the ignition on - If there is any RFI you might hear a buzzing sound - check all the channels. This will prove if your issue is RFI.
Cuppa I'm in melton, but as I'm on-leave at the moment don't have access to a watt meter. if you still have an issue after Christmas - I can bring a watt meter home in the first week of Jan - and check your VSWR.
Reply With Quote