I think I'm down to the MAF with my pinging problem. I've tried in the past to clean the wires with general purpose contact cleaner with little success. I recently found this product and tried it. It seemed to reduce the pinging if that is possible. I reread the instructions and it says to hit it 10-15 times so I did it again. I need another road trip to see if it helped or not. Stay tuned (pun intended)

 

I've got a 4.0 that will start with the MAF cleaning and cylinder decarboning one of these weekends. Let us know how it goes.

 

I just got my valve cover gaskets replaced, and also the upper intake manifold gasket, my pinging under moderate acceleration has gone away now. I also had several vacuum leaks that I had managed to overlook (those hoses are sometimes had to spot)

 

Thanks for the comments. I haven't found any more vacuum hoses since the cruise control line was replaced. I read somewhere in the posts that the intake manifolds have defective gaskets - I thought it was the lower though so I've never done it since I wasn't certain of the cause. Could it just be the upper intake? That would be a piece of cake relatively speaking. The vacuum modulator on the tranny looks fine

The pinging only happens when the engine compartment is heatsoaked after an extended drive. Just getting to operating temp doesn't do it.

 

look for cooling system faults

corroded water pump impeller
sludge/rust plugging of radiator/block/heads
bug/debris plugging of radiator fins
damaged area or extra blockage of radiator front
failing fan clutch
sticking thermostat that is opening slowly or only partially

Aeros operate on the ragged edge of cooling in hot summer temps, especially the 4L auto AWD EXT with A/C

heat soaking over temps of the sensitive MAF and IAT can cause improper operation of PCM engine control

i added 2 3" flex drain pipes under the front bumper air dam on mine that feed up below radiator and direct air flow at engine
helped lower underhood temps towing especially on hard pull hills.

 

My wifs windstar had a pinging problem for a while. We had to have some engine work done and the mechanic cleaned the carbon out of the intake manifold and bingo no more pinging and really helped on the power side. This next spring I will change my plugs and may even clean up the manifold.

 

Took a 30 mile roadtrip out to my sailboat today. I tried everything to make it ping but it wouldn't do it. I think the MAF cleaner did it finally!

Prior to this I tried all sorts of things; Higher octane gas, Seafoaming twice, fuel system cleaner thru several tanks, new Motorcraft plugs, air filter, IAC sensor, O2 sensor, vacuum modulator, etc.
To clean the MAF I bought a set of bits to remove the tamperproof screws holding the sensor to the MAF assembly, removed the sensor and sprayed the crap out of the wires. The stuff is cheap compared to the other things I've tried. Be sure that they are dry before re-energizing the MAF.