A vibration/drone just started on my last highway trip. I'm thinking it may be exhaust but... Here's what happens.
At a sustained speed between 55 to 60 mph there is no vibration/drone but when you back off on the throttle you can hear and feel vibration/drone. No change in symptoms if shifted into neutral. However at a sustained speed of
75+ (engine under load) the vibration/drone is constant except when you release the throttle than the vibration/drone stops until the car slows to 60- mph. This is making no sense to me. I can see where either circumstance would occur but I would suspect that it should be one or the other.The mufflers are stock Ford and may be original. Car has 73k miles. I can't say that there is a change in performance/acceleration. Universals appear to be tight and no obvious exhaust to body contact with the rear wheels being on ramps.
What else might I check and how can I tell if a muffler is coming apart internally if that might be the source.
Richard
'94 GT 'vert Under Drive Pulleys Transgo HD2 Reprogramming Kit High Stall Torque Converter
4:10 Gears Gripp Sub Frame Connectors (welded) Laser Red