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1993 F250 5.8L 8600 GVW 4X2

I just bought a 1993 Ford F250 truck, 5.8 L V8 [vin "H"], heavy duty, regular cab, 4X2, long bed, C6 tranny, 8600 GVW, 177,000 miles! (but only paid $1600.00).

It has changed hands many times, and the most recent owner apparently never did much maintenance... almost all of the fluids were WAY LOW! (oil 3 quarts low, anti-freeze about 1 1/2 gals low... etc etc). I refilled/changed everything, including ALL filters, plugs, etc... It runs/sounds really good, and idle speed seems to be fine.

Problem is: gas mileage is extremely poor. Even driving without any added weight I am only getting about 8 miles/gal around town driving conservatively (light on the pedal, trying to save MPG's).

Now I am trying to find out what more involved steps I can take. As I said, plugs, oil, filters, fluids, tire pressure, etc... all standard maintenance items have been addressed and engine is running fine... does not leak, smoke, or burn oil, and idles okay.

I am considering things like Replacement/cleaning of: EGR valve, O2 Sensor, Catalytic Converter, Fuel Pressure Regulator and/or fuel pump, MAP Sensor, Throttle position sensor... etc etc

When I purchased the vehicle, I found that the former owner did not have an air filter in the vehicle!, I don't know how long it was operating like this and have no idea what kind of junk could have been sucked into the air delivery system... but once again it runs fine, and I have been using fuel injector cleaner/additive with every tank of gas to make sure things are clean...

Any ideas or advice are welcome and appreciated! -Al snipped-for-privacy@yahoo.com

Reply to
male_nurse
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The fuel pressure regulator is suspect and has been under recall from Ford for some time. Check fuel pressure and whether regulator has been replaced yet. If not, they are usually inexpensive at Autozone.

Reply to
lugnut

5.8L is a thirsty engine, not much better than 7.5L. From what I hear, only about 2-3 mpg better. I have the same truck but with 7.5L. I get 11 on the highway, I think you should be getting about 13 on highway in a F250 HD. It is a base F350, big heavy truck. Since you have C-6, no overdrive, another contributor to poor mileage.

Measure your MPG on highway only for a meaningful comparison.

If you have cruise, try to keep the RPMs as low as possible, see what kind of mileage you get.

O2 sensor - definitely. With 177,000 miles, it is almost certainly bad or not functioning. Which means the computer defaults to an entry and runs rich. Running constantly rich will carbon up your EGR valve.

Replace O2 with a quality O2, whatever came with the truck. I hear Bosch is not the best. AC Delco is better. A bad O2 sensor will definitely cut your power and mileage by 1-2 mpg.

Take off EGR and clean it with brake cleaner, or better yet, replace it. It might be stuck in the closed or open position. Resulting in poor idle.

Something else you can do is get a compression test. I hear that engines with high miles just won't give you as good mileage as new. I have a GM V8 and I replaced everything I could think of to get above 20 mpg it used to get and still get only 18mpg - and that's conservative highway driving, on cruise without throttle bursts.

I don't think TPS is a normal maintenance item and I don't if it has any impact on mileage. Does it? Can you pull codes on it and see what it says? O2 by the way, ca go bad without setting codes.

In conclusion, if you get 13-14 mpg in highway only driving, set on cruise, you are doing very well with this truck.

Reply to
Tarapia Tapioco

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