very loud pinging noise, CV1999
I have a Ford Crown Victoria 1999
Have already done 120K miles
Recently I noticed a loud pinging noise coming from the engine ( like when using low grade fuel though I use premium 95 fuel since day one )
The sound comes at any speed between 40-80 miles going up on hills,going down or in a straight road,it comes all the time
I have changed O2 sensors, intake manifold (upper and lower ), temperature sensor, spark plugs , and ignition control box and nothing worked
Have had it in more than 5 shops including ford dealer but without any improvments ( actually no one could figure out the cause of the problem )
If anyone could help me resolving this I would appreciate it!!