My 79 400 4 speed about 8mpg!

 

Been averaging 10-11 in my 92 5.8 auto. Yesterday I started my sixliter tune up along with a timing chain and water pump. I think my timing chain was about 45k miles over due because it had about 3/4 inch of play (yikes) so that alone will help mpgs big time. Right now I have 147 on the odo. I'm also doing the 97-01 v8 explorer 4 pintle injector swap i'm real exited to see how that turns out. I'm going to drive one week on just the sixlitre tune alone then swap injectors the following week. I got the new injectors on Ebay flow matched for just over a hundred bucks. And i'm going with a 205* thermostat to see if that helps also. Updates to follow!

 

My 88 on the last tank was 9.2mpg...alot of idling/tuning/reving..etc. 351w, C6, 31x10.5s, 4.10s...but my motor isnt exactly stock anymore lol...making about double than factory. And it could still use some more tuning, possibly a new carb or rebuild. before the rebuild I was at 10.5mpg..best was 10.78mpg

 

Is it all stock or set for off-roading?

 

ooo lets see wel i will take a wild guess here cause i never have tried getting mine so here it goes.

78 ranger XLT with 35x12.5xR15 nor re-geared for it, 400M c-6 3spd auto... I bet about 5-6.5 on a good day.... It runs a bit rough and the tranny is having issues so that may cause it. goes through 30 gallons pretty fast, has stock 2bbl motocraft carb 2bbl intake stock manifolds to flexpipe with cherries and out the side infront of the rear tires. I don't usually push it i kind of *****foot it so i don't use a lot of gas but i just got the kick down to work so every once in a while i like to floor it and hear it clunk down and the RPMs skyrocket, and to actually feel those huge 35s pushing me forward like that... It's addicting.

 

I finished my sixliter tune last night and wow is all I have to say. Way more power and throttle response. Im driving to a buddies an hour and half away so ill get some millage numbers soon. If you have not done this yet, put the Cheetos down and go.

 

I did what i could for a tune up, plugs, and a slight carb adjustment which led to a new coil, alternator, battery, starter, and a few small things... Me and my brother were trying to adjust the carb to lower the idle cause it was a bit high and once we did that, we had to turn the motor off so we didn't risk hitting the fan and it wouldn't start. Well i tried my luck with the carb and we got it to barely run and sputter. We ended up thinking the pickup coil int he dizzy was shot so we replaced that. No good... My neighbor who knows a ton about everything comes over to see whats wrong and pretty much fixes it right away because he noticed the coil wires were taped up. Turns out the previous owner cut the 2 wires and when he "spliced" them back together not only did he put the wrong color to the wrong color meaning he put on green on red or whatever, he also did a shotty job with it cause there was on loop connector and then bare wires twisted through it.. So every time it moved it lost connection, my neighbor wen through and re-stripped the wires and butt connected them correctly and it ran but it ran rough. Then i replaced the plugs, my old ones were pretty fouled and it still ran bad, so we adjusted the carb to gt it to stay running for the time being and i had a tech at my work look at it and he discovered in my awesome tune up and mechanical skills i happen to have snapped a spark plug in half. Well he found it out by using a test light under the boot of each plug wire on the dizzy until he found one that wouldn't lower the RPMs and then was nice enough to supply me with a new old plug to repair it. It ran great then he also went in and adjusted the carb according to his ear and it ran real smooth. now everything is worn in and it still runs good but slightly rough at times.

 

I get 10 mpgs on 33s and 355 gears with a 302/ np435 combo that's all I can get don't matter how fast I go 60 to 137 it gets 10 mpgs

 

Doesn't matter......it's what I want to drive !

 

I always average about 10mpg.. since I got the thing, tons of work done, always about 10mpg.

I notice above 60 I start hurting for power and mileage, definitely a gearing issue. I think if I sat at 50 all day I could push 14 out of it. I've tried, I just can't drive like that..

 

Like njneer1 said it doesn't really matter to me i love to drive it, but i think later down the road i will have stuff rebuild and look into having my mileage counter clicked back to 0 to start over, then go from there. I was not told what the true mileage is but i can only assume over 200k.

 

greusom, did you see my youtube video with my old 400? keep working on it, they can be some of the smoothest motors ever. I've hopped into brand new trucks with more stumbles and misses than my old 400 had.

Wish I could spend a few minutes with your motor, I can work miracles on those things..

 

I don't think i saw the vid. I wish someone around my area could have the magic touch with these and teach me the ways of the 400... I am trying to learn what i can but i don't get a lot from the web. Like i was looking up how many quarts of oil it takes and people from this site were talking about how the dipstick won't read correctly and it will be below the safe line and people will go up to 7 quarts before it says it's safe... I did 6 1/2 in mine...

 

I think I got around 17 mpg with my 300 I6 with M5OD

 

We had a 91' that got a best of 16 traveling on interstate and worst of 11. Not to good, but didn't care. We are sort of into Broncos.....