As some of you may know, I've been trying to figure out why the $%?& my mileage suddenly dropped last automn, from 13-14 m.p.g to 9-10 m.p.g, I first attributed it to changing the O2 sensors without reseting the ECU, then winter gas, which were all plausible explanation.

Well, guess what....I had my truck in the garage today and decided to check everything in order to make sure that everything was perfect. I started by checking the plugs condition and gap and made sure that the wires were snapped correctly on the plugs when re-installing. All was perfectlyfine. Then I checked the wiresat the coil packs just for the heck of it , even if I remembered that I had made sure that the wires were all snapped in place when I had done them in spring 2007. ONE OF THE WIRES WASJUST HANGING AND BARELY TOUCHING the passenger's side coil pack, bottom outside tower.[:@][:@]So I snapped it back in place.

I had the head gaskets done by the dealer in october, in the same week that I changed my O2 sensors. So obviously, they mis-installed this one wire. It looked as if it had been pulled on to reach the plug, and doing that pulled it off the tower!!!

So now I have questions.

1- Could this explain the abnormaly low fuel mileage I was getting ????

2- Why was the Disco still running and Idling smoothly ??


Thanks,

Darover

 

A good reason why I like to do my own work. Time is money for them and you probably didn't realize that the wires were such a tight fit when installing. I work on other people's cars all the time and it seems like there are always small "obstacles" that come upwhich could potentially be a problem down the road that the owner would never know about.

I think itshould run all right without a cylinder and it makes sense your mileage would suck. Why no engine misfire codes though? That doesn't make sense.

 

Could be a good reason for bad mileage. As for the engine running pretty smooth, your coil pack was probably arcking pretty bad to keep thing running.

 

Yeah, can't explain the smooth idle either, unless there was some compensation somewhere that I didn't feel or notice.

Although that now that I think about it, the idle did kinda stumble from time to time, but nothing aggressive that would have me wonder what was going on.[&:]

So now I guess that time will tell if I finally found the source of my very bad m.p.g

 

If youunplugged a spark plug for a few seconds while the engine is runningI think you findthat you won't notice a very big difference in how it idles.

 

I'm wondering if pulling the plug while the engine is running is such a good idea. Just a thought.

 

No. My point is that it can run surprisingly smooth down a cylinder (I've never done this with a LR specifically), especially if it was only intermittent as it could have been in this case. The only reason that most people even know that their engine is misfiring is because they get an engine code.

 

Don't worry, I wouldn't try it. But I'll take your word for it. But that's another thing, I never had a light in the dash come on because of this ??? Weird!!!

 

you'll know in a week if your gas mileage goes up. Keep us posted.

 

Probably like Mike said.Maybe the voltage to the plug was just real weak, but not enough to misfire. I'm curious too.