If you all will indulge me, I realize this isn't on my Firebird, but I would like to see what all you sparkplug guru's have to say about these pictures.


The fist picture is the four on the drivers side, the left is the front left plug, the right is the left-rear plug.

The second picture is the passenger side, same layout.

The third picture is one of the worst plugs.


Most of the plugs looked very white and ashy. The drivers side plugs look like they have some sort of corrosion or build-up on them.


Again, this is for my DD explorer, 180K miles. I'm just looking for some input, if you all will indulge me, on how my engine is running.

The only thing those pictures show is that it's burning quite a bit of oil.

That's good news I guess, and not surprising for a 180JK motor. I picked it up this summer as my new DD and winter car, first plug change.

Hopefully you put the same (or hotter if those were colder than stock) heat range plugs back in it
If you feel like messing with it, just try changing the valveseals; that may be where most of the oil is coming in.

I don't know what the "heat" range of those I pulled out is, but I bought a set of Autolite replacement plugs for the year/model from NAPA. I still have the old ones at the house, I'll check tonight and compare the two.

I'd like you to bench test the worst plug and see if it's sparking at all

How would I do that?

You have any idea how long they've been in? They don't look oil fouled to me. If there's oil coming in through the guides, you'll have oily plug thread, which you don't (except for one). Coming past the rings, yeah, you got a little of that happening, but most of that white fluff looks like buildup from various additives they put in the fuel these days. Buildups over a LOT OF FREAKING MILES. Many tens of thousands.

I'm not a fan of Bosch plugs, personally. They always seem to have "odd" issues with buildup of crud on them. Just my personal experience.

I'd put some plain old copper-core plugs in that motor because you're probably going to be changing them a lot more often than every 100K from this point out. If only to check on their condition. You can get 30K out of a set of regular copper plugs in an EFI engine that's running close to properly.

I picked the car up back in August to be my new DD/winter car, so it's "new" to me.

Based on the plug wires and how they were all still in the factory wire-looms that didn't look messed with at all (no marks on the clamps looking like they've been messed with), and how frozen they were in place, I don't know that they've never actually been changed...rolling 180K miles. If they were, it was a very long time ago and the plug wires weren't changed with them.

I put in normal autolite style replacement plugs.

To me, it looks like the original plugs, or maybe they were changed once. I would put in your new set and check the dark one in about 2000 miles.

Usually if its valve seals ,there will be a bit of blue smoke upon startup. White ashy plugs indicates a lean mixture. Maybe a vacuum leak somewhere

I'm about to have a 1400 mile road trip (Round trip). I suppose I can check them when I get back.

As you say, I too, don't believe they've ever been changed and the new set is already in. Simple Autolite replacement plugs from NAPA. This is part of why I don't like buying used vehicles, you get other people's crap.

So that's what 100+ mile spark plugs look like LOL

BOSCH are not FORD OEM so they were changed at least once.. but plugs do last MUCH longer now
especially with unleaded fuel.


hopefully you replaced the original wires too.
new plugs with wires of questionable mileage is a bad recipe.

The ones in my Jeep lasted 80,000 but they looked a lot better than those... just worn. threw in new plugs and wires... good for another 80,000 LOL

By comparison our '05 Grand Cherokee had the 5.7 hemi.

The Hemi has 16 spark plugs which you are supposed to replace every 60,000 miles per the OEM . (owner's manual)

2 plugs per cylinder? I didn't know that. But then I'm a chevy guy.

Some of them were so burnt, maybe they just weren't sparking hardly at all. That may be why they were so black. Fouling out.

I've replaced "Half" the wires...I ran out of time to do the passenger side wires. They will have to wait until I get back from my trip now. Hopefully I will get them done this weekend. On the plus side, even with 3/4 of the job done, the truck is running much, much better.