A couple three weeks ago I asked a question about what causes pinging in an engine. I got lots of good answers and using the simple suggestions I tried to eliminate any of the easy fixes.

It didn't work

I believe CowboyBilly9Mile was about to get into it a little further, before jabbed a bit in the thread, but at this point I'm ready to go back at it with the harder stuff.

So the facts, it's a 2000 Ranger 3.0 EFI 2wd with 100,000 miles. I have cleaned the MAF sensor the best I could, replaced the plugs (with those Bosch 2 annode plugs), put some of that questionable STP fuel injector cleaner in it, and waiting for the weekend to do the Seafoam stuff for the intake manifold. I'm getting no CEL and pulling no codes from the computer. I do have a fresh set of wires to install, but again I was waiting for the weekend. So my activities for this weekend involve many things - replace the wires, do the Seafoam cleaning for the intake manifold, change the oil, radiator fluid, gas filter, and get a new battery (unrelated I hope).

I tested the EGR valve and it checked out okay, it held vacuum and it also pretty well killed the engine at idle with vacuum applied.

Where shall I dig some more? I very much suspect the plugs, but I'm really not sure. This is something that pretty much began happening a short while ago so I don't believe it's carbon buildup.

What about the PCV valve? To be honest I'm not even sure where it is, or if it even has one - the Haynes manual isn't clear on that.

 

Plugs oh plugs ooooooo pluuuugggggsssssss. Bosch don't tend to run good in the Ranger engines.

You have a PVC valve, should be on the driver's valve cover near the rear somewhere. There's usually a hose running from it to the intake manifold. Pull said hose, pull said valve. Shake. If it rattles, it's good. If not, replace. 100K, replace anyways.

Oxygen sensors could be going out, they usually hit the crapper around 100K.

Does higher-octane gas stop the pinging?

 

Not anymore it don't. It lessens them, but it don't stop them.

Someone else mentioned that the engine should only have the Autolight plugs but I didn't catch the reason.

 

Autolite manufacturers Motorcraft plugs, they're practically the same thing.

 

Indeed, the plugs are the same. You can try running some higher octane for a tank. Also, you could run some sort of fuel system clean. Like some STP or something along those lines.


Just read your initial post again and saw that you already tried the STP.