What would cause my 99 Lincoln Town car to knock

from what area?under the hood?

Its sounds like its coming from under my hood not loud but I can hear it today is the second time I thought I didn't have any oil in my car I out 2 quarts in on Friday today I was driving an I heard it again seem like when I applied the gas it did it .... Because of gas being high I have been using regular gas 87 I believe I try when I can to put 91 in I don't know what's going on

I currently have 83,954 miles

If the noise is coming from the front of the engine the timing chain adjuster or related part may be the problem. If it was run out of oil there could be valve train damage or lower engine crankshaft related damage. One other thing to check is to make sure all the sparkplugs are tight. There will be an odd noise if a sparkplug is loose. 99 towncar has a 4.6 engine and premium is not necessary.

Ok I just had my serpatine belt relace cause it had a few cracks in it I had a tuneup done back in June of 2014 ..... I noticed the knocking or tapping sound today an Friday not loud at all but I could here it for some reason o keep having an emissions evaporative system leak gross leak p0455 a test was done using an emissions smoke machine there were no leaks no wetness no smell of gas anywhere the smoke came thru the correct line only thing with this issue is there were wires that ran along my fuel line one was burned just a little they were repaired an secured the service engine soon light went out an just came back on Friday the same code came up again

Put a bottle of Z-Max engine treatment in your Town Car at the next oil change. I’ve had an ‘87, ‘93, and still have a ‘98 Town Car. Once I started using Z-Max in the engine, any engine noises disappeared and it idled and ran smoother and my mpg increased between 1.5 and 2.5 mpg overall. Autozone has the best price on it by itself, without the gas additive.