New spark plugs = Mileage! :D (1 Viewer)

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Mar 19, 2005
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Location
Michigan
Yes, it's true. i replaced my spark plugs a couple months ago and having been the only recent thing I've done to the buggy, i have improved my mileage by a ton. I used to go 210 miles on a tank. in the winter sometimes it was 180, but regularly it was 210. after replacing the spark plugs i can average going 265 miles on a tank! 10 MPG to almost 12MPG now.

okay, so its still not great, but improvement is improvement no matter how you look at it, and I'll take it.
 
That is still bad for a stock 80.
You may want to really tune it up, change your O2 sensors and run some injector cleaners through the gas tank etc.
 
I'm getting about 12 right now, and I'm thinking of getting some new spark plugs and o2 sensors, cause I figure that's why I'm getting low mileage. Stock tires, too.
 
My plugs were pretty clean last week but I found another culprit for my guzzling ways (8mpg). The previous owner did the AFM adjustment to richen the mixture, where you move the gear holding the watch spring. I think it backed off after assembly or something because it was 1/4 turn past the stock mark (like 16 teeth, all I read says to move it about 3 teeth). The previous owner was very good about maintenance, this could have been an accident or an experiment. I just filled it up and can't wait to see if I break 10 mpg. My plugs must be on the hot side to be so clean after running rich. All the crap on my roof doesn't help either (yes, the circus has come to town).
 
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Removing roof rack = +1.5 to +2 mpg highway.

YMMV
 
Before the roofrack, tent, spare on the rack, and huge tires - 12mpg.

l_3f42677b605f4ef87992e53085dd9a4a.jpg


After all that crap - 12mpg.

I'm just awesome.
 
Well done indeed!
 
This week I got 338 miles. Tank is not empty yet, fuel light is on. Gas station is about 3 miles away from my house. So 341 miles for almost a tank. Last week I got 323 miles for 21.22 galons. Got new Spark plugs from Dan almost 2 months ago and it just kept on getting better ever since. My distributor cap, cables and rotor is about 20K miles old. Before new plugs, the worst I got was 250 miles a tank.

So yeah, new ignition parts = better mileage indeed :cheers:

Oh forgot to mention, driving habit matters too. I notcied that if I stay within 60 mph, I get better result.
 
I was getting 12 MPG too, so I changed out D-cap, rotor, plugs, wires, both O2 sensors and PCV valve and hoses (yes, all oem).

I still get 12.

New ignition parts do not mean a thing unless there is something wrong with your existing parts.
 
New ignition parts do not mean a thing unless there is something wrong with your existing parts.

Ofcourse. That goes without saying.

Forgot to mention about my 02 sensors, they are OEM and have about 15K miles on them as well.
 
is replacing the O2 sensors a 1 banana? Cause I am tired of consistantly getting 12 mpg.

My wife hinted at driving from Texas to Pennsylvania to visit family....and I shudder at the fuel bill.
 
This week I got 338 miles. Tank is not empty yet, fuel light is on. Gas station is about 3 miles away from my house. So 341 miles for almost a tank. Last week I got 323 miles for 21.22 galons. Got new Spark plugs from Dan almost 2 months ago and it just kept on getting better ever since. My distributor cap, cables and rotor is about 20K miles old. Before new plugs, the worst I got was 250 miles a tank.

So yeah, new ignition parts = better mileage indeed :cheers:

Oh forgot to mention, driving habit matters too. I notcied that if I stay within 60 mph, I get better result.


You must have a constant tailwind. :D

I broke 300 miles per tank maybe once when I got stuck in a construction zone passing through Georgia on I-75. It forced me to keep off the skinny pedal.
 
is replacing the O2 sensors a 1 banana? Cause I am tired of consistantly getting 12 mpg.

I would think so. That also depends on how rusty the 02 sensor nuts are. Those nuts can be PIA if they are rusty. You can do a search on this or you can look in the link below.

Replacing those sensors will definitely give you a boost.

https://forum.ih8mud.com/showthread.php?t=122432
 
is replacing the O2 sensors a 1 banana? Cause I am tired of consistantly getting 12 mpg.

My wife hinted at driving from Texas to Pennsylvania to visit family....and I shudder at the fuel bill.
Yeah, it depends greatly on how rusted the nuts are AND having the proper tools. [A box end straight 12mm and perhaps a box end bent 12mm and a 12mm open end are all handy. Work on a cold truck.] Experience with the job too but that can't be helped. I can change them out in 15-20mins now but the first time took me maybe 1.5hrs.
 
I didn't see any mileage improvement on my truck with replacing the O2 sensors and no improvement in mostly highway driving by removing the OEM roof rack.
 

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