Hi Guys,
My 04 4.6L is feeling sluggish. Like I'm having to give it more throttle than normal, & MPG's are down of course. I've been running mid-grade (89?) octane gas, (which the truck runs much better on than reg.) for the last 30K miles, I'm at 67K now.
I run Mobil 1 Synthetic, air cleaner is new, 1 new COP (rear drivers #8?), still on original plugs, tranny fluid/filter replaced at 30K, nothing binding with the brakes.
My question is in what order should I look at, or replace the following?
* Plugs
* MAF sensor
* Oxygen sensor
* Cat Converters
* Injectors
I'm leaning towards having my mech clean the injectors. He claims it will help, he connects up to the fuel rails and runs some kind of cleaner through under pressure or something.
What do you think?
Thanks, MB

 

I would start by cleaning the MAF and changing the fuel filter. Remember if you do have a cat problem its covered under warrenty until 80k.

 

X2 on the MAF.

 

x3 MAF and fuel filter if it hasnt been changed/changed in a while

and the cats shouldnt be bad at 67K should they?? mine had 120k when mine stopped up (for some reason) and our farm truck (v10) has a gazillion miles and the cats arent stopped up

 

First thing on my list would be to change the plugs. I changed my 04 4.6 at 83,000 miles because it was sluggish and losing fuel mileage. I had plugs in the engine that had gaps at .074. I'm impressed it even started. I put Autolite Double Platinums in mine and power came back as well as mileage. And while yer working on it, might as well clean the MAF and change the PCV. DO NOT use any anti sieze on these plugs. USE LOTS of di-electric grease on the boots where it covers the porcelain part of the plug. Take yer time and buy LOTS of beer.

 

Labnerd, or anyone....(thank you all for the tips)
Do I need to worry about breaking plugs in the 4.6, or is that just a problem with the 5.4 3v?
Do you know the proper torque?
Will I have to remove the fuel rails?
Any TSB's on replacing them?
Thanks, MB
BTW...the fuel filter was replaced at around 30K, I guess I'll be doing it again.

 

i dont think the 4.6 have problems breaking, all i show is 14 ft lbs, dont think you should remove the fuel rails, there are plenty of TSB's on replacing them, and i think ford recommends fuel filter changed every 30k?

hope this helps

 

we recommend 20k miles for fuel filter replacement, but it mainly depends on where you are and what kind of gas and what not. i've been in mooreville nc for about a year now and i changed my fuel filter with less than 10,000 miles on it and uhhh.... this is what came out

that was taken after i let it sit for an hour or so.

 

- Yea, every third oil change for me (9000 miles). I was thinking about doing it every 6000 ,-as quick as it seems to get dirty around here.

 

yea thats what mine looks like to after about 10k miles, ive got 2 farms to tend to and about 200 cows to feed everyday, so it builds up fast lol

 

On a 4.6, use only Motorcraft plugs, do NOT use antiseize, and torque them to 28 ft/lb. Use dielectric grease in the coil boots when you reinstall.

 

i figured around every 10,000 miles but the fuel coming out looking like that cant be very good for the pump. kinda makes me want to drop the tank every couple years to clean the crap off the bottom or something.

and x2 with glc's post

 

Yea, Motorcraft plugs definitely!! I dropped the tank last winter when I ran new hard lines for the brakes. Cleaned the tank and the fuel pump sock. Tank was dirty, wiped it out the tank and there was still allot of dirt/sand grains inside. Had to use Paint prep and a few clean rags to get all that out. The pump sock is detachable, but a PITA to clean well. It's better just to replace the sock. They get really dirty after a few years.

My original pump went out @ 90,000 miles, this one has 170,000 on it lol.

 

X2 on the beer, it always seems to make these things easier

 

I change fuel filters at about 7,500 miles. I have upgraded fuel pumps twice, 55k and 70k and the tank was clean enough to ignore as were the old socks. Go figure.