Hi,
Just recently bought a 1996 Ford F150 w/4.9L Inline 6 and a 5 speed manual w/overdrive. This truck is totally stock and looks new (only 88k miles). The only problem I have with the truck is that it get a whopping 13 mpg out on the highway at 70 mph. The mileage gets worse from there.

I'm in the process of making several modifications in hopes of improving performance and hopefully gas economy. I'm planning on switching to a K&N FIPK air filter, FlowMaster muffler, MSD multi-spark ignition module (sparks repeatedly for 20 degrees of crankshaft rotation to ensure burn of all of the fuel), MSD Blaster coil and MSD super conductor spark plug wires. Based on conversations from tech support from K&N and MSD, I'm hoping this will get me quite a ways towards my goal, which is to increase to 17-18 mpg.

I'm trying to figure out which spark plugs I should use for this combination... thus far, I haven't been able to get any recommendations. I know someone else who has a similar setup in a totally different truck and he's really pleased with the performance boosts, but he goes through spark plugs pretty fast - he goes through a set every couple of months, which seems way too fast. Any thoughts? I've been searching for iridium plugs, but don't know if that's a waste of $$$ or if it would solve the problem.

Finally, am I missing anything here? I realize that I could have just bought something with a V6 or ???, but this truck really fits the bill, and I got a killer deal on the truck.

Any thoughts would be greatly appreciated... thanks in advance!

Randy
Georgetown, KY

 

When I first got my truck ('92 F150 4.9L 5 spd 4x4) I got about the same mileage as you do. I went through it, replaced all filters, all fluids, brakes front and rear including new hoses, new u-joints all around, and an engine tune-up and now I get about 20mpg on the highway (about 12mpg around town). I'd try all this stuff before going with the performance boosts because if what I've listed are the problems the others won't help.

 

I have had my 19990 F150 SB 4.9 w/5sp, 3.55 gears since it was new. I agree with the change fluids and tune-up first. Some thoughts..

Mileage: I get about 17 city/20 hwy without the ac. Speeds about 75 and it starts sucking gas like any engine in this truck would

Plugs: I have found that the newer style heads like the Bosch +4's, and the older designs like the 4.9's like the conventional splitfire (non-platinum)- which I always exchange at the end of their warranty period which is 2 years IIRR.

Ignition system: Fords system is actually pretty good. Although the MSD might give you a little more in comparison, you realistically won't see much of a difference unless the system is getting tired...at 88k, its likely its starting to get a little weak but check your cost out carefully.....the OEM is really a good unit from a performance standpoint.

FIPK: Really won't gain much if any from that mod. A K&N OEM replacement filter will give you just about what you can really get. BTW...Wix HP filters actually flow better than K&N, search the web for air filter test and you would be supprised at the info! While many will argue the pro's and cons of the FIPK units, the one thing 90%+ agree upon is there is no mileage diference.

Mufflers: With the duel in line cats, about 80% of the noise is absorbed/eliminated, you can acutally just drop the OEM muffler and run straight pipes from the cats. The sound is a resonably deep tone, very similiar to a small V8. I have had that on mine since 1990 and have passed all smog test with no problem. The nuffler you chose as long as it is a quality high flow unit will really have no difference of the flow just the tone.....try it with and without a muffler, you like just what you have!

The 4.9 is an excellent engine and when tuned up will run very wellnext to most small V8's. Perhaps the best upgrade you can do really beside the tuneup and dropping/modding the muffler is a performance chip/programmer. That will help withmileage and hp.

 

Wow. Excellent info here guys I pick up my 96 F-150 4.9L I-6 5-Speed in 7 days from today, and I'll probably need to follow through on a full tuneup and some of these efficiency mods for myself.

What do you guys think about removing the fan, fan clutch, etc, and installing an electric fan assembly. I believe I read that one can save up to 3mpg from this type mod.