Hi Scotty - My 2003 Mercury Grand Marquis makes an odd noise intermittently, has been doing so for about 2 years now and runs great otherwise. No one has been able to figure it out (including me!).
- Sounds like low pitched rumble, coming from engine compartment or underneath. Can feel vibration in floorboard.
- Lasts about 2 seconds
- Only happens when in 1st gear and accelerating
- Only happens when the AC is on.
- Does not happen at idle. Does not happen all the time (20% of the time when accelerating, AC on, in first gear)
- Same symptoms > 2 years now...
My mechanic tried replacing all the coils in the car - that didn't help. [ Didn't hurt either, other than my wallet 🙂 ]
Should I just keep ignoring it? Or is there a smarter way to figure out root-cause! Thank you sir!
Money does the same thing it should be fine but check the spark plugs and coils, air filter, and anything else that might help the engine
