2001 Ford f150 supercrew 5.4l 4x4 w/ 212,,000 miles

All new spark plugs and coils - running great compared to when one of the coils went bad.

Just wondering if this is "Normal" for these 5.4l engines or if I have another very small Running issue that I need to find.
The engine doesn't run "Dead on Smooth" when warmed up idling nor when the truck is in gear, stopped, and idling. Is this" Normal" for these 5.4l ford engines? It Almost feels like a ever so slight miss but yet it is running better than it ever has since I have owned the truck. It has done this since I have owned the truck.

(to compare it to other vehicles..... I have had mid 2000' chevy 5.3l engine trucks, a chevy 6.0l truck, and a few 5.7 liter Dodge hemis and those all idled Very Smooth).

Wondering what Your Experience is with the 5.4l Ford and how Smooth your engines have idled?

Thank You

 

I bought my 2002 5.4 in 2009 with 69k miles on it. It always idled very smoothly with no missing. But lately with 164k miles on it, it has a slight miss at idle. I've been thinking about what could cause it. I've recently cleaned the throttle body and IAC. The spark plugs were changed at 119k miles. I've been considering installing new plugs and possibly new coils since they are original. Perhaps there is a small vacuum leak or small egr leak. I don't know. A year ago when I drove it over 6K miles on vacation, a couple of days it was missing at idle pretty bad at the end of the day after running it on the interstate all day. Both times the next morning I bought two bottles of Gumout for high mileage engines with PEA and poured them into what was left of that tank of gas and ran it until almost empty and that cleared up the missing at idle. I have been known to pour a couple of ounces of gumout into the brake booster vacuum hose and let it run down into the intake when the engine wasn't running. That may have helped a little. Like I said, I've been pondering this issue too for a while.

As additional useless information, I also have a 2005 Dodge Magnum with the 5.7L Hemi bought new. It has 114k miles on it and it always had a slight miss at idle except for about 1,000 miles after a spark plug change when it did not miss at idle. Spark plug changes are every 30k miles for this engine.

 

remove and clean the IAC (for starters) then also check your PCV hose. It is common for the "elbow" that attaches to the pcv VALVE to become ...rotton. Lastly run a couple tanks of GOOD GAS to clean up the injectors. I have had to address all 3 of these items on my 01 5.4. currently cracked intake manifold at water crossover by #1.(285k miles)
With the new plugs and coils......would assume you used a HEAVY bead of dielectric GREASE around the plug boot to "seal" it to the head?

 

The elbow is actually at the back of the intake, the hose runs from the PCV valve. Techron is the best additive to clean injectors.

 

2 days ago I tried something similar to what I Think you had described
I pulled the air intake piece off the front of the throttle body, squirted about 200ml (a 6th of a quart or so) of MMO into the throttle body, re-installed the air intake, waited 6 hours and then drove the truck for about 20 minutes. I was thinking the MMO might loosen up something or clean something out.
Yes, it smoked out the tailpipes for about 10 of those 20 minutes and a check engine light came on, looked under the hood and discovered I had forgotten to hook the electrical air/connector back up to the intake.

Ok, now a new issue..... idles at about 700rpm when warm but then goes up to 1000rpm and then back down to 700rpm, does this about every 30 seconds.
I am thinking I have forgotten to hook up some other wire or hose but I cannot find anything that is disconnected? Have I missed something?
I am going to pull the air intake back off and see if I have missed something. In the mean time... **What would cause my new idle fluctuation issue please kind Sir/Anyone?

Thank You for all the help so far on this!!

 

vacuum leak, IAC hung up. FWIW pouring stuff in the motor without it running is NOT a very good idea. All it does is sits in the intake....waiting to be sucked up by a cold engine. A more preferred method would be to remove one of the large tubes on the side of the AIR INTAKE HOSE (like the IAC tube) and squirt XXXX in while truck ins warmed up and RUNNING allowing it to be atomized in the airstream to wash down the the internal components. NOT TOO MUCH at one time.....don't want to hyrdo-lock the motor..

 

I following Directions...

I removed the IAC and sprayed it several times with carb cleaner with in between use of lightly using q-tips to absorb and remove some of the black inside the IAC.
Re-installed the IAC... still the same problem.
While the engine was running I sprayed shots of carb cleaner in all the areas of the engine and there was no idle change so I am pretty sure there is no vacuum leaks.
Also with engine running I pulled the PVC out of the passenger side valve cover and put my finger over the PVC and it was sucking good air/ it sucked my finger right onto the PVC opening so I am assuming the PVC system is working correctly, good suction at the PVC opening.

I am picking up a Duralast Brand IAC at my local Autozone here shortly, its spendy, near $50 but also has the limited lifetime warranty.

Ill check back after I have installed the New IAC.

Thank You

 

I just finished installing the New IAC. The Idle and what not seem to be back to normal.

Engine still has that ever so slight ruffness about it when idling, stopped and in gear. (Running great though, no misses.)

When I get down to a 1/4 tank of gas I will try some of the Techron that glc suggested and see if maybe the injectors are slightly dirty and the stuff will clean them out.

Thank You Gentleman for all your suggestions and help!!

 

Hi glc;

Which Techron exactly, to use in the fuel tank?

 

https://www.walmart.com/ip/Chevron-T...10-oz/16647989

2 bottles, then fill the tank.

 

Mine is a 2000 with 5.4l. It vibrates slightly at idle. If I just touch the gas slightly it is smooth. I only have 89,000 miles though. I have thought about bumping up the idle slightly, but it runs well so I just ignore it. I also have shot weatherstripping, and mudder tires, so it is not the most quiet vehicle to begin with.

 

How do you plan on bumping up the idle? It's electronically controlled. Idle speed adjustments went away a long time ago.

If the spark plugs have never been changed, at 89k it's due.

 

I put the Techron in the gas tank a week or so ago, no change in idle.

I am guessing this engine may have always idled like this.

I eventually will change the fuel filter but I am not too excited about getting under the truck now that its getting colder and the wind has picked up. The truck wont fit in my garage at this time, unfortunately.

 

It doesn't take much time to change the filter but you will need a special tool to remove it.

 

don't forget to evaluate the vacuum hose over by the battery???...that goes to the a/c unit.. about 6" piece IIRC ..1/4" hose. I also recommend using zipties (as hose clamps) for the 2 large hoses attached to the air intake . Do not recall what they are ...lol... but they are 5/8" or 3/4".
I just did an intake swap on my 5.4. From a coolant leaking plastic to a 1999 ALUMINUM ...runs like a sewing machine now (about the same amount of power too...) Not bad for 285,000 miles....it's tired but dependable!