Do a search in this forums for pinging and you will find a lot of items that will make your car ping.
Mine pinged at about 3000 rpm and this is what I did chasing the problem.
1 Adj. timing to 10. Still pinged
2 replaced 02 sensors. Still pinged
3 replaced atc sensor. Still pinged
4 replaced ecc sensor. Still pinged
5 installed Kirban Adj. fuel pressure reg. and guage. Still pinged (but found out I need a new fuel pump)
So thats were I am at right now I need to replace the pump and see if my pinging is gone.
I had a big pinging and knocking problem the timing was advanced so I set it back to stock. Still had the same problem and I use 93. Put on the off-road H-pipe and pro dumps and I can run 87 with out any pining or knocking go figure LOL. Don't know what I did but I fixed the probelm . I for got to mention that I had my MAF cleaned and that fixed my problem of Full throtle and no go problem so that might have fixed the pining problem too.
I have a new fuel pump, ACT sensor, the MAF is clean (I am getting a new Pro-M though), and the O2's aren't throwing any codes. I have heard though that the 02's my not make codes? I will put the timing back down to 10* and see what happens. It may go away with my new MAF though since I have heard that solves so guy's problems. It doesn't ping when I maintain a constent RPM, only under partial acceleration or WOT. Don't know if that helps.
You mentioned that you changed the ACT sensor. How about the ECT? They can become very lazy, yet not through a code. If the ECT is sending the wrong temp, then you're computer will not adjust the injectors correctly = pinging.
Anyone have the part number on the ECT sensor? Can anyone tell me where it goes exactly? I thought it went on the front on top of the radiator but on a site it said that it went on the passenger side of the intake?
I got this part # from my Ford shop manual CD......12A648
The ECT sensor is located behind the upper rad hose between the distributor and the alternator. There is an electrical connector attached to it. You'll need a 1 inch deep socket (or a crescent wrench) to remove it. A little bit of coolant will leak out when you remove it.
A piece of advise.....FIND A DIFFERENT FORD DEALER!!!!!!!!!!! Any dealer that can't find an ECT sensor for a 5.0 is beyond hope! They obviously have no idea wtf they are doing.
One more thing....when i replace my ECT sensor last month, I bought it from UAP Napa.....a little cheaper there.
Thanks a lot. I wasn't sure if a part store would carry it, but I needed a part number. My local dealership is actually one of the best in the region, it was just the kid in the parts department that is a goon. Thanks again.