So truck has 5.2, 145k, airgap, tuned by henifever, 180 t stat, no cat, and has always pinged really bad, as far as I can remember anyway. So I got around to pulling plugs and they all look like the truck is running really lean, and actually one plug, number 8 has no electrode at all, I'll Attach a pic. I'm starting to think it's because I have no cat, both o2 sensors are in there but don't throw a code. But I'm starting to think they're reading the same voltage, so I bought some new plugs today I'm gonna throw them in there but I might put a fouler or spacer in the second o2 sensor, any opinions?? Thanks!

 

The lack of a cat won't make you run lean. First, verify fuel pressure is good. Then, I would consider having a chat with Hemifever. What tune are you running, and what fuel?

 

I was under the impression that the o2 sensors are reading the same thing because of the lack of a cat and can be throwing off the wideband. I might check fuel pressure also that's a good idea. Me and him had some words one day concerning a faulty tuner and whatnot. Don't think confrontation would go over too well. Now I'm in a predicament unfortunately. I'm running a 87 canned tune and 87 octane fuel.

 

The rear O2 only measure cat efficiency. It's the front one that has the greatest effect on mixture. The rear *might* have some minor impact, but, that one doesn't have a hard and fast answer yet.

Have you tried running 89 octane, and see if it's any better?

 

I'm going to throw some 93 in her tomorrow and see if anything changes, maybe a better plug will also, I got some NGK platinums.

 

I know I have a bad vacuum leak, I can tell by "wacky vents" I've tried finding it and can't seem to find it anywhere or the back check valve, I'm led to believe it's somewhere under the dash. And no cruise control either. But 4wd works hmmm

 

Skip the platinum plugs. A fair few folks have had real issues with 'em on our trucks. They just don't seem to like them. Just go with some good coppers.

Find your vacuum leak. Cruise not working would prompt me to start looking over by the cruise module, which is cleverly concealed under the battery....... a vacuum leak will tend to make you run lean, which promotes spark knock.

 

Oh really? I'm surprised, I'm guessing they were designed for copper plugs.. ? I've had the vacuum leak for years, I have to figure out a way to find it I guess. There's a clear cut in the line to the cruise control for some time now, but when I cover it with tape, I still have my vacuum leak. I'm thinking that might be the lean issue. I don't mind not having cruise control I just don't want the leak.

 

I have seen too many folks chasing a random misfire, that goes away when they get rid of their 'rare-earth' plugs..... Some folks like 'em, but, they are most certainly in the minority.

Get some appropriate size rubber line, and use that to patch the old and brittle plastic lines. Tape doesn't always seal as well as you would like.

If you don't use the cruise, could always just pull the line, and put a cap on the port too.

The cruise servo itself is sometimes the source of the leak. The battery pees on it, and eats holes into it....... It's a real drag to get to though.

 

lol that's true, maybe I'll get some coppers, auto store had a deal on these good plugs so I just got them.
I might have to do that, I've been chasing this vacuum leak for years, I just have to get to the bottom of it now.

I throw some 93 octane fuel in it this morning, didn't notice a difference at all with the pinging.

I've heard that the battery acid sometimes leaks on it, I'm not a fan of cruise anyway.