mustangman94,
Here my UNDER A BUCK pinging fix!
After replacing nearly every sensor in my car in an attempt to cure pinging, I finally cured the last remaining bit of it by finding and fixing two small vacuum leaks.
After doing everything else that everyone else tells you, look for vacuum leaks everywhere! Even a small one will result in lean A/F ratios and cause pinging.
The most important vacuum leak I found, and the biggest cause of the pinging problem, was an old, brittle, leaking Fuel Pressure Regulator vacuum hose. This is the small hose that connects the FPR to the intake manifold. Mine was the original piece and it was hard as a carp! It was so brittle that I had to cut it off. I had no flex left in it at all and was definitely leaking at the intake manifold nipple.
A vacuum leak in the FPR hose actually causes two problems. First, the fuel pressure doesn’t change correctly in proportion to engine load anymore since the FPR vacuum diaphragm isn’t getting the full manifold vacuum signal. Second, an air leak there allows un-metered air into the intake which the MAF never sees and thus incorrectly calculates load as a result. And our fuel/spark tables are what? Load based!
The hose is only about a 5 or 6 inch piece of 5/32 inch ID fuel hose. The hardest part was actually finding a 5/32 inch ID fuel line. It seems not to be a common size. I could find 3/16 inch ID fuel line at most car parts places. Though it’s not the best fit, it will work until you can find some 5/32 inch, which is a good tight fit. (Don’t try to use any thin-walled tubing for this, the vacuum will flatten it out and close off the hose. It’s got to be thick-walled fuel line or thick-walled emission control line.) The Ford dealer doesn’t stock a special formed hose for this part. They will just sell you a chunk of hose off a reel, but for three times what it will cost at an auto parts store.
The second one I found was a very small leak caused by an old, brittle, PCV valve grommet. This is the large diameter rubber grommet at the back of the intake manifold into which your PCV valve plugs. When that leaks, you are sucking outside air into the intake, instead of oil fume laden air from inside the sealed Positive Crankcase Ventillation system. Again, the MAF never gets to see this air and the engine runs lean, causing pinging.
Our cars are over 10 years old. Most of the rubber and plastic stuff in the engine compartment is toasty and brittle after years of enduring the under hood heat. Anything carrying an intake vacuum signal is suspect. (Don’t forget that there’s one that runs into the driver’s side fender well where the cruise control vacuum diaphragm is located!)
I would replace your FPR vacuum hose first and see if that does it. It will only cost you a buck to find out.
Good luck.