After starting my car (1986 xj6) this morning I noticed that it is very loud, almost sounds like a muscle car. I do have the oxygen sensor warning light on, could that be linked to the extremely loud reving? It has never sounded like this in the past. Any help would be much appreciated.
Thanks.

 

Bad exhaust gaskets, or where the manifold bolts to the exhaust pipes.
This can seem to happen overnight & is common in ANY car with this age.
Any exhaust shop should be able to handle this. The gaskets are only like $6 each. But can be a real pain, because of rusty bolts.

If the pipes are rusted & cracked, you can look at spending about $400. Because that area is a B***H to work in. You can buy replacement pipes, but could wait weeks for them. The exhaust shop can do it right then & there.

 

Interesting problem, I wonder if there is a hole or a crack in the manifold right under the heat sheild.
t is possible but unlikely that the sensor has fallen out.

JusyV12

 

I had the same problem happen to me on another car. Problem was exactly what espresso said, cracked head gasket.