Hey guy's. I have a 1999 F-150 XLT supercab flareside with the class III towing package, 3.55 limited slip rear. I just bought the truck used with only 22,000 miles on it from an older gentleman and his wife. I was astounded with the condition of the truck. There is not a dent or scratch on this thing. Even the bedliner looks new!!!
Anyway, I've noticed while sitting at a light it seems to idle a little rough. As soon as you accelerate or even at speed it is as smooth as silk. Is the idle quality a little shakey on the 5.4 and I am just over-reacting because it is a new-to-me truck or is there something I can do to smooth it out? Also, with the towing package that is on my truck, is there an oil and transmission fluid cooler? Thanks guy's.

Mike

 

Although I'm about as new here as you

Yes, I believe you have at the very least a beefed up tranny cooler with that Class III. Oil cooler I'm not sure on. As far as the rough idle goes, from what I have read a lot of our trucks have a rough idle and only the only cure seems to be trial-and-error parts replacing. Not a cheap method. Have you tried pulling your codes or resetting the computer?

 

do a search for ...Rough Idle/Engine Miss, posted by 36racin. You will find more information then you want to hear about this subject. Sorry that it will not be what you want to hear. This rough idle cannot be fixed. Your best cure would be to hurry and sell it before winter,as you will find out that it gets worse in cooler temps.......

 

What am I one of the few with a 5.4 that idles perfect?

Also I don't think it could be so bad that you should turn and sell it. It is by the way still under warrenty. Before I would look into selling it I'd talk with Ford and have them look it over.

I too am new to the scene and after finally getting an F-150 I don't see how I ever lived with out it.

 

I think that selling a car due to a rough idle is a little extreme! Idle quality in a engine is dictated by tune and electronic control from the fuel injection system. It is not like the truck is about to stall, the rpm's stay just where they should, it's just not perfectly smooth.
I was just looking for some ideas on where to start. If I can't figure it out I'll let the people at Ford worry about it.

Thanks.

 

A slighty rouch idle seems to be inherent in most 4.6 and 5.4 engines. My 97 4.6 had it. My 2001 5.4 is less noticeable but it is still present. After taking my 97 in for warranty service on at least two occasions, one of the chief techs said that it was just the way the truck was. I've come to agree with him. The reality is that unless it is really bad, you only really notice it as a slight vibration in the steering wheel when waiting in gear at a light. Nothing is perfect.

As to the tow package, if it is a factory install, then you will have a frame mounted hitch reciever, a 7 pin connector, an oversize radiator, a transmission oil cooler, and maybe an engine oil cooler. Your radiator should be about 2" thick at the core as opposed to 1" for the stock radiator. You should also have received a wiring harness which permits you to easily hook up an electric trailer brake control, and if you do not have both 4 pin and 7 pin connections at the hitch, then you should have received a little converter thingy that permits you to connect a flat 4 pin wiring harness to the 7 pin connector. Finally, the tow package gives you an upgraded alternator (100 amps, I think for 99, but I could be wrong).

 

Thanks for the Info Beast!
The only time I notice the idle is just like you said, at a stop light in gear but it is very slight. Other than that I cant belive how smooth the engine is! I did receive the converter for the 4 pin that plugs into my 7 pin connector. (the people that had the truck before me never towed anything with it so all the parts are still wrapped up in the box!) I also noticed that the battery in my truck is quite large!!!

I am planning on using my truck to tow for the first time this weekend. I'll be trailoring my Mustang to the dragstrip!!!

 

The heavy duty cooling/tow package includes a heavy duty radiator (well, it's supposed to, but many don't), transmission aux. cooler (look thru the lower part of your bumper and you'll see two coolers. The driver's side cooler is for the power steering and the other side is the tranny cooler), and water to oil engine oil cooler (mounted between the oil filter and engine block).

As for the rough idle. Some of our trucks have computers that seem to lean out the fuel/air ratio to the point where it idles rough. Sometimes, you can determine if this is the cause if you reset the computer. You do this by turning everything off. Remove the negative cable from the battery. Turn the headlights on for 5 minutes to drain the power backup in the computer. Turn the lights off. Reconnect the negative cable to the battery. Start the engiine. If it idles smooth, then you know what's causing it. As far as I know, this particular rough idle can't be fixed.

If it idles rough, then it's probably something you can fix. Do a search on "rough idle" in this forum and you'll find every possible fix for it.

 

I too, have a 5.4 in a SuperCrew with over 58,000 miles and it idles very smooth. It is not silky smooth through the entire powerband like my 7.5 EFI, but it is generally smooth running. I have noticed that in some instances, and I think it is probably fuel quality related, the truck will have a slight tremor with the a/c on at a stop light in hot weather. I try to use only Exxon, Mobil, Chevron etc fuel because it seems I can use their regular grade without the detonation problems that I get out of the bargain brand regular fuel.

 

TIMBERGHOST,
I HAVE TO AGREE WITH RJ AND MANY OTHERS HERE. YOU HAVE THE 5.4 ROUGH IDLE PROBLEM AND YES IT WILL ONLY GET WORSE AS THE WEATHER GETS COOLER. MY TRUCK HAS BEEN IN THE SHOP 5 TIME OFFICIALLY AND STILL NO FIX. I AM CURRENTLY GOING THRU THE DSB PROCESS WITH MY TRUCK. FOR THE IDLE PROBLEM AND SOME OTHERS. ALL WE'VE BEEN GETTING FROM FORD IT THE "NO PROBLEM FOUND" OR "IT'S A CHARACTERISTIC OF THE ENGINE" ANSWER. IF IT WAS A CHARACTERISTIC THEN WHY WOULD ALL 5.4'S NOT HAVE THE ROUGH IDLE? AND THEY DEFINATELY DON'T. HOW COME THE HIGH END NAVIGATORS WITH 5.4'S AREN'T EXPERIENCING THE PROBLEM? HOW IS YOUR GAS MILEAGE?? MINE GETS AROUND 12/13 MPG. FRIENDS WITH THE SAME TRUCKS AND ENGINES GET AROUND 16/18 RANGE.
SORRY TO LAY ALL THIS BAD STUFF ON YOU BUT YOU NEED TO KNOW. WE HAVE TRIED EVERYTHING WE CAN POSSIBLY DO TO GET OUR TRUCK RUNNING CORRECTLY AND YET THEY STILL RUN BAD.