Audi misfiring


My 1998 Audi A6 sometimes feels like it is only running on three or four cylinders . the enginge light comes on and starts flashing…last week the exhaust got really hot when this happened and the mechanic said it got up to 500 degrees…they put new plugs in, it ran fine for two days, then it happened again for a stretch of about 5 miles (gradual uphill) after getting to the top and going downhill for about 4 miles it was fine and has been fine for two days…mechanic said it may be the O2 sensors…code says that 3 and 5 are misfiring…we can’t seem to make it happen again …any ideas?..thanks

In the future it would be a good idea to get the exact code It will be in the format [P1234]. It is generally not a good idea to drive a car with a flashing CEL.

Did anyone look at the plugs that were removed? What did they look like?

I wonder how the mechanic figured out that 500? F.

The O2 sensors would never cause this. You might need another mechanic.

Does this engine have a distributor cap and/or plug wires? Change if they’re original.

If it has multiple coils then swap #3 and #5 with others.