Eigen, it's not that I consider my advice in high esteem, I just don't like giving out bad answers or supporting the gambling approach to fixing things. Normally, I won't speak unless I know. Bad answers/advice may improve a persons post count but those are posts I don't need attached to my name is all. And the person action on bad advice doesn't win. There are some common causes for engine knock but a few are different for the 3.0 as opposed to the 4.0. Thus, to avoid my giving you bad advice and thus a bogus suggestion or two, I had to ask. Good to know all is well in the end.

*JJ, I won't discuss that here; it would be .

 

Oh it's not skin off my nose. I don't always acknowledge replies to a post simply because its a forum and everything here is entirely voluntary. I wouldn't take it personal because I didn't reply to you, I did see your post, however I was in fact looking for very generic and basic information. I didn't want to solve my particular problem here, I wanted to know some basic aspects of pinging and engine systems so that I could then approach solving my own particular problem from a rational way.

It's just who I am, more concerned with overall concepts than specific details.

Anyway, I haven't actually said my problem is fixed per se, I suspect it is, but so far I haven't had a chance to put it to the test - after all driving on the interstate in Puget Sound Washington isn't something someone does lightly during rush hour. So far it runs just fine, so I'm not gonna worry it to death unless it comes back with a vengence.

The MAF sensor was not what I personally would consider dirty, however after resetting the computer and cleaning it off the truck's overall performance showed dramatic improvement. I can't recall the name but someone else recommended maybe giving the EGR one more once-over before writing it off as good - I can do that too (it's a free test!). As well as dumping a bottle of 4 dollar injector cleaner in to see if maybe some crap dislodges - after 100k the injectors are bound to be somewhat filthy (although I have my doubts as to the effectiveness of that 4 dollar cleaner).

I do need to replace the wires, but that's unrelated to the pinging in my mind. By the way, I have seen references that the plug performance can also effect pinging, maybe by not burning the fuel well enough. Has anyone seen data comparing the factory plugs with those Bosch 2 electrode plugs? I was curious as to whether or not they were in fact not getting the job done?

 

So I applied vacuum to the EGR during idle and the truck ran pretty crappily. that combined with the fact that it will hold a vacuum tells me that the EGR valve is working just fine. So that eliminates one more thing

 

Did you try the seafoam?

 

You want to stay away from anything except the Motorcraft/Autolight plugs. There are a lot of post's of people that had to change out the bosch/other plugs.
Dave

 

No, I haven't even tried the cheap/easy Fuel Injector cleaner stuff. I wanted to do the minimum first, cleaning off the MAF and testing any parts to see what shakes loose first. Only if the truck continues to ping or begins to ping again soon will I take the next step.

Changing too many variables at once will make it impossible for me to figure out what actually cured the problem.

Personally I have to wonder if simply resetting the computer was in fact what improved my performance more than anything. If the problem comes back in a week or so that might indicate that the computer reset cleared out any bad data it had stored, but the underlying problem still exists and therefore it loses its ability to compensate as data signals begin to show trends again. Maybe I'm reading too much into the truck's computer.

 

Seafoam can be used for cleaning injectors but I am referring to using it to "decarbon" the intake and cylinders. If you will follow the directions on the bottle to suck it in through a vacuum line (I use the brake booster), let it die and sit for about 15mins, you will be amazed at the amount of cabon you blow out the tail pipe. This isn't snake-oil or a cheap fix, it's just cleaning parts of your engine that you have neve cleaned before. Carbon buildup can and will cause severe aitflow issues in the intake as well as "peaks" on the head that will be hot enough to preignite the mixture.