My old carbureted 300-6 did better than my dads 96 300-6 in the mileage dept. The 300-6 was a good engine just don't expect any speed out of it.

Never did hand calculate the mileage but I don't think my old 79 F-150 4x4 ever got any more than 20 mpg. Dads fuel injected truck F-150 2wd wasn't that great on fuel

 

I had a 91 F150 with the I6. It was a great engine, had great power, and some decent speed. Fuel mileage was around 14 in town, and 18-19 on the highway. The best part was the torque. It was a monster in that department!

 

I had a 93 f-150 w/ I-6. I can't remember what the MPG were, but I did have over 265k miles before the transmission (auto) gave in; than I sold it. The motor still ran strong though, with no smoke.

 

Thanks for the replies, guys! So it sounds like it's quite fuel-efficient engine for a truck, right? Is there anything else that will pull my load and get better mileage? Just wondering. I did find an '89 extended-cab model w. the 4.9L 300-6 and 5-speed manual in great shape with 192K miles for just under $1000. It has been owned and very well maintained by a service tech it's whole life. Is this a good deal?

 

own 79 F150 4x4 with 4.9L it tough engine. It get 15-19 mpg.


I wish they include 4.9L in F350 I would buy if I see.


Use motorcraft oil filter FL1A for that engine.

Don't rev it hurt.

you get best mpg by stay 2,000 rpm.

 

I had a 89 in line 300 in a f150 5 spd great truck . My mileage was 15 highway . I had about 1500lbs in tools . My f 250 had a auto 3 spd with 411 rear gears same mileage . John

 

I worked at a camp in Wisconsin that still has 6 or 8 of them in thier trucks. One or two in vans as well. No idea of mileage - it was all 20 mph or less, around camp use. Turth be told, they disposed of a truck that year that still ran very well, but you could lift off the bed on the drivers side by hand. They finally decided that old F250 was more of a safety risk than it was worth.

You may be able to buy something with better fuel economy, but you'll spend more buying it.

 

Like everyone else........around 20mpg empty...........15 loaded......not a speed demon but just alot of pulling power....good engines

 

1988 f150 with the 4.9L efi and a ZF 5 speed tranny. 15-17 towing a 6x12 open trailer. 19-21 on the highway.

 

i had an 89 efi I-6 in an 89 f150 2wd. had 172k on it before i sold it. Didn't use one drop of oil and i pulled with it everyday for 3 seasons. best damn 6 cylinder ford ever made. they should be beaten to death for replacing for the new ^%$$&* 6 cylinder. has awesome torque and pulling power but don't expect to go fast.

 

I had a 94f150 with a 4.9efi. its been a long time but i think it was only around 14-17mpgs. it wont win a race, but it will pull a bit slowly accelerating. i sold it in 01' with 175K on it. i just moved down the street to the guy i sold it too. he still uses it daily and i see it all the time and want it back just like every other truck ive owned

 

1988 f150 with the 4.9L efi and a ZF 5 speed tranny. 15-17 towing a 6x12 open trailer. 19-21 on the highway.

Not to bump an old thread, but if your f-150 has a zf5 someone swapped it in. It didn't come stock.

The manual that came in the f150 was an m5od, and considered light duty. The f-250/350 got the zf5 manual, which is a HD trans.

Btw you can still find the 300 in f250/350s. It's mainly going to be in the 87-91 body style. Hard to find after that.

 

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What are the specs on the ZF5? HP, MPG, are they available for my 89 F150? Would I be better of sticking with my I6 or would it be worth a swap? Keep in my I just had my engine get gone through and had a cam put in it plus headers and exhaust.

 

I am thinking about buying an Inline-6 F150, and wondered what you guys thought about them. I am particularly curious about the fuel mileage. I don't need something with a lot of power or off-the-line zip, but just something that will tow a small load decently, and get great mileage.

Fueleconomy.gov says that the 85' and 86' carbureted 300-6 got 24 and 25 MPG highway, and then dropped down to 20 MPG highway with the introduction of fuel injection in '87. Anybody have some opinions on this? I did run into a guy that owned a '65 F150 with this engine, and he got 26 MPG. That sounds amazingly good. Will the EFI really get that much worse? Just wondering.

I will only be towing about 2000-3000 lbs. at the most with it. If there are any other options besides the Inline-6 that get great mileage and will still tow I would be very open to hearing about them. Sorry for the long post, but I would really appreciate good info about this. Thanks.

I've owned two of 'em. One in a 1980 F100... still having flashbacks to that previous life. The truck got about 18 mpg. I pulled a couple of things with it and it had no problem. Wasn't fast, but who cares? I got over 200,000 miles out of that one. Finally it spun a main bearing.

Right now I have a '93 F250. Much heavier truck, and it has the 4.10 gears in it with the 5-speed manual. Fuel injected. Slow, burns quite a bit of gas (I'm actually afraid to measure it), but it will pull anything. I've pulled small track-hoes and skid loaders with it with no problemo.

BTW, I thought that I'd heard somewhere that this particular engine wasn't introduced until 1972. I know Ford made a smaller 6cyl that they used in the older half-ton trucks that was more in the league of the old 235cid engine found in the old Chevy trucks or the Chrysler straight 6. I'm not sure about this though, just sayin'...

 

Still thinkin about getting one, and still puzzled about whether to get a carbed or EFI. I sure like the '92-'96 interiors a lot better, but don't know if it's best to go with an older one. I have gotten to see a few older carbed 4.9's, and they were just wonderful. Not really fast, but excellent torque. Any more opinions? BTW, the first year of the 300 straight-6 was 1965.

 

You'd be crazy not to get EFI. The 351/460/300 went efi in 1988.

 

Still thinkin about getting one, and still puzzled about whether to get a carbed or EFI. I sure like the '92-'96 interiors a lot better, but don't know if it's best to go with an older one. I have gotten to see a few older carbed 4.9's, and they were just wonderful. Not really fast, but excellent torque. Any more opinions? BTW, the first year of the 300 straight-6 was 1965.

Cool. That's good to know. Thanks for the info.

 

Hey while we are on the subject. My first question which was MPG has been answered. What I am seeking for now is additional info with my 89 F150 I6 which I purchased 2 years ago. The truck has turned into a major project as I repaired/replace like 50+% of the whole truck. Lots into it. I am planning a drive from Massachusetts to Florida. What are some fluids, tools, and maby even some new parts that you think I might need. As reliable as the trucks seam to be for the most part, my truck has been constant problems. Fortunately they have been getting resolved and I am confident in the truck but I feel like I should be prepared for something to fail.

 

It won't be the in line 6 that strands him on the side of the road. It will be a fuel pump, break line, ball joint, steering pump etc...

He does probably have the t-18 which is a super simple and reliable tranny. I've seen these rebuilt trail side.

The truck has turned into a major project as I repaired/replace like 50+% of the whole truck. Lots into it.

This means your half way there.

You'd get more responses if you took your questions to a Ford website that has a forum for these trucks but people here will still help with their experience.

This is great advice.

 

Zf-5 is the transmission.


If I was you I would just rent a car for your trip.

 

Zf-5 is the transmission.

If I was you I would just rent a car for your trip.

I am going to spend time with an old friend and I also am interested in getting in on some hours there so I will need my truck. About the tranny, I have the 4 speed manual. Is the Zf-5 a 5 speed and is that an automatic or manual?

 

It's a 5 speed manual.


Do you have the knowledge and tools to repair what sounds like a well used truck on the side of the road?

 

It's a 5 speed manual.

Do you have the knowledge and tools to repair what sounds like a well used truck on the side of the road?

Really good to know about the transmission. I have some experience and fair amount of tools. The truck is an antique now but it's very solid and reliable. You would love my truck! It's an XLT Lariat loaded power everything. For an 89 it's my baby.

 

Has anyone had the ground issues with any of their efi I6 F150’s? I had the problem and with help from numerous mechanics there have been several grounds put on my truck. If you have any questions about it I will do my best to help.

 

You'd get more responses if you took your questions to a Ford website that has a forum for these trucks but people here will still help with their experience.

If you just had it rebuilt there isn't anything you need to bring if it was done properly.

Any external parts that might fail are available from practically any parts store across the nation and are dirt cheap.

If you've got a 4 speed manual you probably have a T-18 like I do in my F250. If you don't haul much or enjoy rock crawling with your truck you'd probably enjoy a 5 speed more. Both the ZF 5 and Mazda tranny from that time frame perform good behind the 300.

They have overdrive so you can safely cruise at higher speeds.

Almost every old vehicle will start experiencing issues with poor grounds, wires, hoses, vacuum lines etc if they aren't inspected regularly and replaced when worn. I bought an 89 F250 with a 300 in it 2 years ago and have put 15k miles on it, driving it almost daily. Nearly everything was original so I've been replacing all that before they fail. Sometimes I didn't get to it soon enough and you'd find me in a parking lot performing roadside surgery, but it was never the engine that was an issue.

If you really enjoy your truck and want it to stick around the best advice I have is to avoid revving it over 3k RPMs, especially for long periods of time. The harmonics on any straight 6 are pretty rough. Your power band is all there in the low end anyway.

If you maintain it properly and don't overrev the engine the truck will fall apart around it.

There are also some forums out there created specifically for ford straight 6 discussions, you'd probably benefit from checking those out too.

 

Thank you to you both.

 

I am thinking about buying an Inline-6 F150, and wondered what you guys thought about them. I am particularly curious about the fuel mileage. I don't need something with a lot of power or off-the-line zip, but just something that will tow a small load decently, and get great mileage.

Fueleconomy.gov says that the 85' and 86' carbureted 300-6 got 24 and 25 MPG highway, and then dropped down to 20 MPG highway with the introduction of fuel injection in '87. Anybody have some opinions on this? I did run into a guy that owned a '65 F150 with this engine, and he got 26 MPG. That sounds amazingly good. Will the EFI really get that much worse? Just wondering.

I will only be towing about 2000-3000 lbs. at the most with it. If there are any other options besides the Inline-6 that get great mileage and will still tow I would be very open to hearing about them. Sorry for the long post, but I would really appreciate good info about this. Thanks.

Im not a ford guy but ive made a lot of money working on them. As far as the 4.9 300ci 6 cylinder ford engine its prob the best one they ever made. When it came out it was competeing with the Gm v8. In the 1/2 ton class it hauled more weight got better mileage had more torque and in the long run is hard to kill. It has been dubbed the unkillable engine in motorhead talk. If you can deal with the quirks of ford trucks and its not smoking leaking or knocking and the price is right you may want to jump on it. With care , upkeep and some tlc you can see 200k on the odometer prob wo any major work. Fuel pumps and twin tank switches crapping out. Egr tubes and valves rotting are common. Vacume leaks are common. And blend door issues will happen. The vacume tubes under the hood near the firewall where the ac system is rot out from the engine heat. Tiny plastic lines unprotected and sticking out for no reason will be first place to start when your blend door starts flapping and air stops coming out of the vents and shoots out of the floor vents when you accelerate. Go to those hoses first. Ive had success cutting back to where there is only a couple inches of tube on each end and using hose that tightly fits along with marine shrink to secure the hose to the tube will generally cure it for years. Hope this helps.

 

And the dreaded cold start wrist pin knock...LOL These engines were used a lot for irrigation pumps on farms, tons of them still in use. They have never been considered fuel efficient by any measure in pickup trucks.

 

My 1996 F-250 4.9 liters inl-6 have 135,000 miles on it. These fuel tanks have to be come off and clean inside and it resist rust really well. The rear fuel pump was bad and I replace the front fuel pump for MFI-EFI and the replacement pump is worth $250.00 dollars for each. I plug up the color blue gas line between the rear tank and front tank. The rear tank will come off for inspection myself.
The tank removal is terrible long time than any other car and truck. Use vacuumed cleaner to make fuel tank properly clean. And the pro shop mechanic don't have vacuum cleaner. But I have best tools including vacuum cleaner wet/dry.
The air injection manifold, intake manifold and exhaust manifold all are in the motor as parts together. The air inj. Manifold break easily when taking it off from cylinder head so I let him bronze welding and plug up two injection threaded holes with two bolts and the weld seals the manifold (bronze). It runs on 4 air injector light blow just fine. Before it was 6 air injection. At 120,000 miles replace the hydraulic lifters they are to keep lubricated for cooling and I hope it is with hollow pushrods. thanks for reading.

 

The exhaust cast iron manifold needs to be check and find and feel the leak from big crack in underside exhaust manifold. It need to be replace at 120,000 miles for 1994 - 1996 F-250 F-350 and F-150 gas at LKQ salvage yard for used parts.