I picked up a ScanGauge last week. So far, it's pretty cool.

This morning I fired up my '99 Disco after sitting idle all weekend.

Ran rough at first, and I got a flashing SES light, then steady. Read the code with ScanGauge and got P0306.

Roughness went away after just a few minutes, but since the P0306 code, the ScanGauge is reporting about 1/2 the MPG as I was seeing before the code???

Any clues why it has changed. Going by what my gas gauge is reading, it doesn't seem like I'm getting the crappy mileage its reporting.

Thanks!

 

Don't quote me but, I think the 0306 code is a misfire on cylinder #6. Don't know what that would have to do with gas mileage? Unless it is constantly misfiring, that would effect mileage I'm sure. I would look into why it misfired though, if that is what it is.

 

I dont know what that code means.
But any mis fire will reduce MPG.
A mis fire means that cylinder(s) is not firing correctly, and when that happens it does not burn the fuel as efficiently.
Less efficient fuel burn means lower MPG.

 

From what I can find P0306 is indeed a #6 misfire. After it threw the code and I reset, the Disco has seemingly been running fine, yet mpg is still in the toilet.

Plugs are fairly new, I have new wires ready to install. Where else would I look to find the reason for the misfire?

 

First, help us, how many miles on the engine, what octane gas are you burning, when was it last tuned along with new 8 mm plug wires?

Also, a Scan Gauge is not very accurate when determining mileage. Track it the old fashion way, mileage divided by gallons so you know for sure.

 

'99 Disco 2 with 117k.

O2 sensors, Plugs and wires in July

Ran Seafoam through it via instructions on here in August

I usually run mid-grade or premium fuel

I have no clue how the ScanGauge gets it's fuel numbers, but I thought it curious that before the P0306 I got one reading and after I get something about 1/2 of the previous.

Thanks!

 

Whos plugs and wires did you install?
Quit using cheap gas, you loose mileage and power and can carbon up the valves.
As for the mileage drop, sure it will go down cause now you have one cylinder not carrying its own weight.

 

Changed thermostat today and checked all my wired... Found #6 had a huge split in the wire. Last time I changed, I bought a cheap set... all the parts place had at the time.

Guess I'll stop tomorrow and pickup new plugs and some 8mm wires and do it "Right"

 

I would try a set of 8mm Magnecor wires they seem to be the best for our trucks. They are expensive at about $100 per set, but not that expensive when considering the lifetime warranty. People also use Kingsborn on the forum but I have no experience with them.
I have had my Magnecor wires on for 35,000 miles and no misfires. The are a little thicker silicone wires that take the heat well from our hot V8 engines. Well worth considering. I think they come with a lifetime warranty, only downsid is you need to order them online. Check my signature for a link. Not the cheapest price but you can price shop it through Google Shopping

Here is where I bought mine.
http://www.lrrforums.com/store/index...oduct_id=29893

 

Ordered up a set of 8mm Magnacors...

Took a while to pry the money out of my account though... That's a chunk of a set of wires.

I don't look forward to wire swap, but if it is good for my rig, I'll suffer through it.