motor lacking power
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Joined: Aug 2003
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From: Carl Junction Missouri
motor lacking power
I have a 1988 3/4 Ton Ford 4 Wheel Drive. It has the stock 5.0 302 V-8. Before purchasing the truck i though that it would get good gas milege. But it only gets 8 to a gallon. The engine has 160000 miles and I am thinking about my options. 1. Rebuild the engine, clean injectors, and add "fuel saving products" to it 2. Replace it with a 351 W or something simular 3. Replace it with a 360, 390, or 400 4. Replace it with a V-10 I am 17 and I need to consider how much it will cost, how many problems it will have and of course what the MPG is. Any information or input would be greatly appricaiated. Also I cannot decide to keep the stock 5 speed or go with an automatic. I need to know what the best combo is for power, touque, and miles per gallon. I want all i can get for my money.
Senior User
Joined: Nov 2000
Posts: 201
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From: Drayton, ND
motor lacking power
Coming from a guy that rebuilt and installed a 351w into an '84 f150 that had a 302, I would highly recommend staying with your 302 when it finally does get to the point that you can't bear it anymore. It's ten times easier to reinstall and there are performance mods, upgrades and parts all over the place. I would tend to stay with the 5 speed also, depends what the main uses of your pickup are.
Post Fiend
Joined: Mar 2002
Posts: 19,402
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From: Bonita Springs FL
motor lacking power
You bought a 3/4 ton truck for the gas mileage? 
Keep in mind that you have a fuel injected motor. Going to a carb setup will be a little more complicated than keeping the EFI. I'd say keep the EFI, as would a lot of other people. Going this route will rule out the 360, 390, and 400, although they're all great motors.
Something that you should look at is your axle ratio. If you're running 4.10's it will have a major impact on fuel economy. If you're planning on keeping the truck for a while, it might be worth thinking about going to a higher ratio.
8 mpg is pretty poor mileage in any truck though. Have you pulled the codes? I'd start there. You could have a bad sensor sending crap to your computer and throwing the whole motor off. Sometimes these fixes are cheap and effective.
And of course, a tune-up can bring new life and mileage to an old engine if it's been neglected.
Also.. not every motor will play nicely with your transmission. The modular engines (4.2, 4.6, 5.4, and V10) all use a different bellhousing pattern than your transmission will accept.
Keep in mind that you have a fuel injected motor. Going to a carb setup will be a little more complicated than keeping the EFI. I'd say keep the EFI, as would a lot of other people. Going this route will rule out the 360, 390, and 400, although they're all great motors.
Something that you should look at is your axle ratio. If you're running 4.10's it will have a major impact on fuel economy. If you're planning on keeping the truck for a while, it might be worth thinking about going to a higher ratio.
8 mpg is pretty poor mileage in any truck though. Have you pulled the codes? I'd start there. You could have a bad sensor sending crap to your computer and throwing the whole motor off. Sometimes these fixes are cheap and effective.
And of course, a tune-up can bring new life and mileage to an old engine if it's been neglected.
Also.. not every motor will play nicely with your transmission. The modular engines (4.2, 4.6, 5.4, and V10) all use a different bellhousing pattern than your transmission will accept.
FTE Leadership Emeritus
Joined: Sep 2000
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From: Southern California
motor lacking power
Are you running oversize wheels like 33's or bigger?
What's your axle ratio?
The combination of oversize wheels and numerically lower axle ratios makes for pretty unexciting performance. Even though the engine RPM is low, fuel milage still seems to suffer because you always have your foot on the floor trying to get it to move.
What's your axle ratio?
The combination of oversize wheels and numerically lower axle ratios makes for pretty unexciting performance. Even though the engine RPM is low, fuel milage still seems to suffer because you always have your foot on the floor trying to get it to move.
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Joined: Aug 2003
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From: Carl Junction Missouri
motor lacking power
Hey, thanks for the input. I am running LT265's. The axel ratio is, i belive, 3.55 or maybe 3.50 so it is geared pretty high. My main pupose for the truck is daily driving. If their are anymore question i would be happy to answer them in my search for better gas milege.
Junior User
Joined: Feb 2003
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motor lacking power
while you can pull the codes, I'd start with the basics first - change all your fluids/filters/plugs/wires/, etc., then reset your ecu by disconnecting the negative battery terminal for ~ half an hour. Run through ~3 tanks of gas, the first one use a can of BG44k injector cleaner, and see if you've improved, after the third tank.
Also switching to synthetic fluids can pick you up a modest mpg gain.
Also switching to synthetic fluids can pick you up a modest mpg gain.
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