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I have an 86 F150 4x4 with a 5.0L EFI, and a 4 spd. I drive about 30 miles round trip to work, and my mileage is terrible, I am averaging half a tank a day on this trip. I have done all the tune up stuff, plugs, wires, cap, rotor, fuel, air, breather filters, but still am experiencing the same. I know being a 4x4 with the 4spd I shouldn't expect much, but this seems ridiculous.
Thanks
It could be anything. Check your pressure. I was getting terrible mileage and heard a faint hissing under the hood. Turned out that I had a bad fuel pressure regulator. See if you can get anyone, or you can, get the fuel pressure while running.
First pull codes. that motor should be efi correct. how many miles are on the motor and what size tires are you running? also check your oil and smell it for gas. that alone will tell us a lot as well. let us know
Yes it is EFI. It has 75 thousand miles. Oil looks good. I had 31's on it, and just changed to 33's, but it was the same with the 31's. I thought maybe the sending units in the tank were off, but they are working properly. The truck runs great, has no rich fuel smell. It does idle up when I come to a stop with the clutch in. It jumps up to about 2000 rpms, and I can pull up on the foot feeder and it idles back down. The truck is in great shape, and original miles for an 86.
whats the engine temp at? those 33's are not helping i will say that. what is your rear gear ratio? for only that many miles something is for sure wrong. how fast are you driving that 30miles each day?
and the oil looking good is different then smell. reason is if the fpr is bad or some injectors are stuck open it may dump raw fuel into the motor which will cause other issues like blowing the motor for instance.
Temp runs between 160-180. Sorry, when I said looks good, I was refering to everything, but it does not smell of fuel. I usually drive between 50-55mph to work. As for the gear ratios, they are stock. I know the 33's dont help, but 4mpg out of a EFI 302? It was the same condition with the smaller narrower 31 inch tires I had on it. Unless sometime in its life someone put lower gears in it, and I do not know about it. I know going to the bigger tires did not affect performance, it will still get up and go like it always did.
ok your engine temp is way to low. you should have a 195 tstat in there. otherwise the computer will think the engine isnt warm and use more fuel. what rpm are you at when going 55? that will give us an idea as well. but pull codes www.fordfuelinjection.com will show you how using a paperclip and 15mins of your time at most.
So the 195 should help? thank you for all the help. I will check the rpms on the way home today, and get back on here, but in the mean time I will check the codes.
Thanks.
Thanks for all the help. I changed the thermostat yesterday. I drove around all day, even did some trail riding, and only used 1/4 tank. Hard to believe all that because of a thermostat. Thank you again for all your help Kemicalburns.
no problem, glad its working better. might change out plugs as well or at least inspect them because it they are sooted up from running a little rich youll gain even more mpg now.