i just finished the tune-up on my 92 f150 5.0l, put new wires, plugs and cap and rotor. we checked the firing order, it was good. the performance seems abit better but on my way to town i burned a quater tank, when i was burned half a quater before the tune-up. i did have my front hubs locked, can that make a difference?

 

Yes, considering the typical condition of the front axle U-joints in most trucks(seized or partially seized from lack of use), the increase in drag will have a noticable impact on fuel milage.

P.S. Beside that you cannot use the fuel gauge to calculate or even estimate fuel milage, these things are notoriously inaccurate.

 

okay but my top end is a little more sluggish too. in 1st, 2nd and 3rd it seems better then it used to be but it seems to have more touble getting to 60+mph, in 4th and overdrive

 

What brand of plugs, wires, cap/rotor did you end up using?

RE: https://www.ford-trucks.com/forums/1...old-truck.html

 

i went with champion plugs/wires and cap and rotor. i was going to buy from ford but they wanted 100 bucks for wires and couldn't even get the cap. my truck just takes a while to get to 60mph ever since we installed the new parts.

 

What plug gap did you set the plugs at? Did you verify you have the correct firing order and properly space the plug wires away from each other? Cross-fire is a very common problem on these trucks.

 

we gapped the plugs to what it says in the manuel and checked the firing order and everything

 

Just to verify and point out an important often overlooked item:

The firing order for 1987-1993 5.0Ls is 1-5-4-2-6-3-7-8. If #7 and #8, or #2 and #4 spark plug wires are routed next to each other at the separation bracket, an induction crossfire condition can occur.

Make sure the plug wires in bold are routed away from each other.

 

i'm pretty sure thats the firing order we read in the Haynes repair manual. its just in overdrive i can barely get over 100km/h otherwise there is lots of power in 1st, 2nd, 3rd and fourth. i know in overdrive its not going to have lots of power, but it used to be better than it is now in OD. can you post a pic of the plug wires in the right positions on the cap if you can?

 

courtesy of steve83

I would also suggest to check the base timing. If you got one plug terminal off you could have effectively retarded the timing.

 

me and my dad will have to take a look at it when we get time.

 

swap those out for auto lights.you'll thank me.

 

why are autolites better? will they make much of a difference?

 

I have found that if i use champions in any of the fords i have owned, they do not last long. After my first experience with champions in a ford, I was told fords don't like champion plugs. don't know y but the ones i have owned don't. seem to always burn them up in short order. I use autolites ever since then and have had good life span out of them. i also have used the e3's with good luck. had one go bad so i just replaced them with autolites. with the e3's in my 94 escort, got about 1 mpg more than regular.

 

Yeah, Get Motorcraft or Autolite plugs.