Any suggestions?
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Any suggestions?
I have a 1988 F150 that I just finished rebuilding the motor in. It is a 4 wheel drive with lockouts, C6, 351W, 3:55 gears. I am not satisfied with my mileage since I started driving it last week. It is getting about 10 mpg and seems to be running great. Plugs look clean and chalky white, exhaust looks clean as well. Maybe I am expecting too much, I am not sure. I was kinda expecting more like 13 mpg. The injectors were professionally cleaned during the rebuild, so I think that should be ok. All sensors are also new, however I did block off the EGR valve during some troubleshooting early on and have not undone that. I would think that would only help mileage. Maybe the engine just needs to be ran for a period of time to break in better? Any ideas will be grealy appreciated.
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From: Sussex
I hate to be the one to break the news to you, but you are expecting too much. The motor is tight, so it might get a little better. I have a 92 F250, 351W, E4OD, and 3.55's and I get 12-13 in town, and 15-16 on the expressway. I think the 10 neighborhood is about what you're going to get.
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From: Ottawa, Ontario
Is the 351 stock or modified? Headers? manifolds?
A brand new motor will take some time to loosen up, and milage and power should improve. My experience seems to indicate best hwy milage is obtained when the engine is kept under 2000rpm. That may only be 55-60mph for you depending upon tire size.
A brand new motor will take some time to loosen up, and milage and power should improve. My experience seems to indicate best hwy milage is obtained when the engine is kept under 2000rpm. That may only be 55-60mph for you depending upon tire size.
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From: Ottawa, Ontario
Originally Posted by 77bigblock
It's a windsor. They stopped making modifieds in the early 80's
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Joined: Jul 2002
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From: Bend,OR
a chalky white plug means your running a tad lean. have you pulled codes? www.fordfuelinjection.com will show you how. what is your timing set at? stock is 10* btdc with spout connector removed. if your running it easy (55mph & under) during the first 500 miles running dyno oil. get a few oil changes in every 500-1000 miles then once you hit 3000 miles on the motor switch to synthetic.
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I appreciate all the info guys. To answer a couple of questions, yes it is a windsor. No it is not modified. Still has the cat a resonator and 2 1/4" single exhaust into a single turbo muffler and turndown. Set the timing with engine up to temp, spout connector pulled, to 10 degrees BTD. Checked total timing after re-installing the spout connector @approx. 2000 rpm. Came in about 22 degrees. Haven't pulled any codes, since I haven't had a check engine light. Would there be codes to pull? Runs great, just don't like the mileage. I am planning several modifications to help all this out eventually. Probably start with exhaust, since I don't like it the way it is anyway. Also, anyone have a success stories using K&N Filters or high dollar plugs?
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From: Ottawa, Ontario
Originally Posted by jamespud
Still has the cat a resonator and 2 1/4" single exhaust into a single turbo muffler and turndown.
Originally Posted by jamespud
Probably start with exhaust, since I don't like it the way it is anyway.
Originally Posted by jamespud
Also, anyone have a success stories using K&N Filters or high dollar plugs?
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How about those throttle body vortex spacers? Anyone want to give me a testimonial about them? They are supposed to improve gas mileage and horsepower. I don't believe everything I read, especially when written by a salesman.
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Joined: May 2003
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From: south louisiana
The K&N style filters are NEVER a waste of dollars. TB spacers and high dollar plugs are. The K&N's flow more air and are reuseable, and these two facts make it a good deal for the money. If your mileage increases due to the engine not having to suck as hard to pull in air, it will improve the mileage some, how much is a 64 million dollar question. Also helps to remove the factory intake silencer leading into the air cleaner box. Even Ford recommends this mod in addition to a K&N style filter in the Ford Racing catalog and their 5.0 book. 
Last edited by baddad457; Nov 19, 2006 at 11:44 PM.
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Thanks again guys. I have already removed the intake tube going to the airbox that mounts on the top of the core support. I was thinking about making a new one though that pulls air from somewhere other than on top of the radiator. It just doesn't seem right to pull air in from above a heat source. Probably have to break down and buy some shorty headers and redo my exhuast to make a real difference. One the guys commented that it is screaming down the highway with 3.55's and a C6, he could not be more accurate. Thinking about changing to taller tires which would drop the rpm at highway speeds.
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I just re-checked my timing last night and found that it was about 13 degrees advanced instead of 10, so I changed it to 10. Not sure if that will make any difference on mileage or not, but worth a try. Evidently something has changed since we set it initially or maybe I didn't get it right to start with.