Gauge Cluster Problem.
Okay, so this is my 7th mustang but my first of this body style, I just bought a 2005 Mustang GT Manual its got a Power Akoustic radio in it (the previous owner put it) but as soon as i drove off the lot my gauges started messing up, like my RPMs werent reading at all, speedometer wasnt working, and neither was my coolant temp gauge... so i take it back to the dealer and ask them to run a diagnostic test on it, they said it could be the after market radio.. could that be true? ive never heard of that nor does it make any sense. Thanks!!