I have recently purchased a 95 f250 with a 5.8 W. It has lees than 100,00 miles on it and very little rust. I'm looking to increase the gas mileage on it and was thinking about starting with the oxygen sensor and new spark plugs plugs. What would be a decent and non-expensive after market spark plug? I'm also open to other ideas on increasing the gas mileage.

 

I would go OEM Motorcraft plugs they're not much maybe a few cents more, K&N Filter, the oxygen sensor probably wont do much unless its throwing a check engine light, a light foot goes a long way. I would probably invest in a new cap and rotor too with wires.

 

Not a lot you're going to gain unless it's messed up now (which isn't uncommon in older trucks).

Most advice here is to stick with basic Motorcraft plugs, that the higher dollar ones are at best a waste of money and maybe don't even work as good (I don't know, I haven't tried any).

There's something on here called "the 6 litre tune-up" (after the screen name of the guy who originally pushed it, I guess). It's basically just a slightly hotter coil, good wires, cap and rotor, and then gapping the plugs a little larger. It's not bad, but it's not magic either.

K&N filters are a love 'em or hate 'em proposition. Some people swear they help mileage, others swear at them for messing up sensors. I had one on a Jeep 258 six and an '02 PowerStroke. Didn't see any benefit (or problem) on either one.

Get the timing set right. Clean filters and keep an eye on codes can't hurt. And keep your foot light.


For a bigger project, I've heard that the combustion chamber on the stock heads isn't great, and that you can run higher compression on regular gas with some aftermarket heads. I'm intrigued with the idea of building a 351 for good mileage and driveability. But I'm sure there'd be no way you'd gai enough to pay for a project like that in any reasonable time.

 

Thanks for the input. Was thinking about a hooter coil and a new distributor but wanted to see what happened with new plugs and o2 sensor. I'm not a fan of K&N tried them on a previous ride and did not get any results.

 

Keep ignition stock.

Long tubes, compression, porting are things that increase mileage. Whenever you're tearing something down to fix broken things (leaky head gasket for instance) make it better by doing those things above.

 

02 sensor does make a difference if it's over 100k or so. The sensor becomes "coated" and reacts slower with the rich/lean signals. It become "lazy" as we call it. Rather then switching 10-15 times a sec, it may only do it 3 or 4. this switching is what is called fuel trimming, ex a bit rich, shut 'er off, to lean richen'er up and so it goes. Replace if older