you and me both, since the larger gap the exhaust smells a lot less rich. Almost as if I can hold a lighter to it and it might not catch fire. I’m going to be rechecking everything in two hundred miles, see what the plugs are looking like, see if the plenum is sucked in again somehow. Truck has a glass pack and a cold air intake so I’m not sure why it runs this way when it is less restricted.

 

If it were a V10, then only a little ridiculous.

 

here’s something I just thought about, the truck since day one That I’ve owned it, it’s had a misfire in cylinder 2. No check engine light for the miss, only seen on a scan tool with the capability to see misses. So it’s not enough to trigger the CEL but you can feel it at idle or stop at a redlight. She just kinda shakes and doesn’t stop.

 

Plugs are NOT the reason bad mpg. Get things back to stock and start there. And deal with the misfire. Good grief already.

 

Yeah, need to find out what the misfire is all about. Cold air intake, and glass-pack aren't going to affect gas mileage. Think I would have a look at what PCM thinks engine temp is, when it should be fully warmed, and also have a look at fuel trims.

 

your opinion is your opinion. My truck runs like garbage no matter what, plugs are plugs I find that now that I have these tuned in it runs a ton better than champs ever had it run. And yes, yes plugs will effect mpg, if the gap is wrong the spark can’t burn all the fuel, if they’re worn out they won’t burn all the fuel.

 

didn’t think about this, I’ll hook up the snappy later on and see what the computers talking about

 

So what year is it? And how many miles on it? Timing chain helps quite a bit if it's stretched. Where is the fuel sync set? EGR valve if it's a 94 or 95. PCM temp sensor if it's an earlier truck that had 2 temp sensors. Some after market PCV valves flow too much air causing a vacuum leak you'll never find.

 

2001, 70k engine from a fleet maintained truck, fuel sync set to factory specs with a snap on scan tool

 

Plugs are not the reason you're getting 5MPG is what I meant. Goodness! But I guess you don't need any more opinions anymore after asking for them. So I'm out. Good luck.