Has anyone experienced a hard miss at about 1500 rpm, My wifes 97 Expy has the 5.4 and it has started to miss at low rpms with just a little pull on the thottle. If you step into hard, it clears up and goes on. I thought it might have been the dreaded Converter shutter that I had on my truck. Change fluid, filter and drained TC. New Merc V and still same story.. The Expy has 71K miles, thought it could be injectors, or maybe coil pack? or MAF...
Any Ideas?

Thanks
This has got to be the best Ford Board around.

 

LAKE,
MY 99 F150 5.4 HAS A INTERMITTANT BUT VERY NOTICABLE ENGINE MISS WHILE DRIVING. IT USUALLY HAPPENS AROUND THE 40 TO 45 MPH RANGE. HAVEN'T PAID ATTENTION TO THE RPM'S WHILE IT'S DOING THIS BUT WILL GET BACK TO YOU WITH IT. ALSO MY TRUCK HAS THE ROUGH IDLE/ENGINE MISS AT IDLE. I JUST FILED FOR A DISPUTE SETTLEMENT BOARD HEARING ON THIS PROBLEM. SOMEHOW THEY MUST BE RELATED. WHAT KINDA GAS MILEAGE YOU GETTING WITH YOUR 5.4?? I GET AROUND 12 OR 13 MPG WITH MINE. AND FRIENDS WITH THE SAME TRUCK AND ENGINE ARE GETTING AROUND 16 TO 18. GOOD LUCK WITH YOURS

 

36racin,
Thats sounds just like what this is doin, we get 12.5MPG no matter what we do. Sounds like something is very similar here. I think I might try the MAF, have you replaced yours?

Thanks for the info.
Lakenut.

 

I have the same problem with a new 01 screw with a 5.4 Mileage between 12-13 all around. Hestitation between 1500 and 2000 rpm with normal throttle. This just started about a week ago. What has your dealer told you about it? I had a 97 expy with a 5.4 and it was a 4x4 and it got 17-18 on the hwy. I will see my dealer sat morning. I will let you guys know how it turns out, this is not acceptable by any means.
Terry

 

Terry,
Can't wait to hear what the dealer says. Mine has 71K no ext. warranty so I am on my own on this one..
Thanks

 

Lake, I had a 98 f150 with a 4.6 that did the same thing. The dealer could not find an error code and it took about 6 visits to finally get it right. They gave me a small plug in computer that had a push button on it. When the vehicle would act up, I would push the button and it would record what was happening. The recordings they got indicated a fuel delivery problem. An engineer at fords tech help line said to replace a coil pack which forever fixed the problem. My current truck is acting the same way. I just hope it is not so hard to find and correct this time. On my first visits, they said nothing was wrong with the old truck. I will update tomorrow.
Terry

 

LAKE AND TERRY,
I HAVEN'T TAKEN MY TRUCK IN FOR THIS PROBLEM. BUT I DID LIST IT AS A PROBLEM WITH MY TRUCK IN MY LETTER TO THE DSB. SO THAT IT COULD ALSO BE ADDED IN TO THE PROCEEDINGS. MY TRUCK NOW HAS AROUND 26,500 MILES ON IT SO ITS STILL UNDER WARRANTY. BUT MY DEALERSHIP IS REFUSING TO WORK ON MY TRUCK AGAIN UNTIL AFTER THEY GET SOME GUIDEANCE FROM FORD OR THE DSB. WHAT GETS ME IS THAT SOME TRUCKS HAVE ALL THE ROUGH IDLE, ENGINE MISS, DRIVE HESITATION, AND POOR GAS MILEAGE. SOME HOW THEY HAVE GOT TO BE RELATED.

 

A "hard miss" is usually an ignition problem and is usually one of the coil packs if it is on a "coil-over plug" [COP] engine. Intermittent misfires are not recorded in the OBD II system. If a coil misfires for around 2 minutes contiuously, then it will set a code. 5.4L engine owners that have COP engines should start by check the rearmost coil and sparkplug on the passenger side (#4 cylinder). The heater hose clamp above the #3 & #4 coilpacks seeps and drips onto these 2 coils. If the evidence is not obvious, remove the sparkplugs from these cylinders and look for rust on the base of the plugs. The front 2 cylinders will have "clean" bases on the plugs and the rear cylinders will have rust. If this is the case, inspect the 2 coil packs visually looking for small hairline cracks in the epoxy of the top surface. Replace the spring clamp with a wormgear clamp on the heater hose. Install new plugs @ $1.99 each. If you found an obviously bad coil pack, replace with new from dealer @ $46.50each (they come complete with new rubber boot). If no obvious defects are found, reinstall the old coil packs but put the front 2 coil packs in the rear 2 cylinders; this way the suspect coilpacks have now been moved to the front where they can be easily changed. I would put the coilpack from the rearmost cylinder (#4) in the front (#1) where it can be changed in about 5 minutes without any disaasembly other than removing the coil wire and the one anchor bolt. Bottom line is get those 2 coil packs out of the back where they are inaccessable and up front in the open. Rusty plugs are almost a dead giveaway that the coil pack is damaged.

 

I also think it is a coil pak based on my last experience with the 98.
I took my truck to my selling dealer today. I went on a test drive with the tech to make sure they undersood exactly the problem. Good thing to, since the service writer did not, he wrote up the problem was under heavy throttle when in reality it is under normal driving between 1500 and 2000 rpms. I do not want to knock the service writer, he was very good to me. Unfortunately,,,, the tech on duty was a jr. tech and he was stumped as he could not find and error code. He was able to see the problem while we did the test drive though. I will have to wait until monday when the sr. tech comes in. PLEASE NOTE,,,,, Another seasoned mechanic happened to be standing in the office when I was told that no code was found, he said that 90 percent of the time codes will show, 10 percent will not and that he was not surprised. ALSO,,,,,,, I got a 98 ranger supercab to drive while my truck sits. So far so good, dealer is taking care of me. My truck also has a bad ac compressor. Oh well, I have had 6 so far and they have been excellent, I hope this one is no exception. I will type again when I have some news, they are saying tues or wed. Take care all,
Terry

 

Good call on the Coil Pack...
I ended up repacing all of the plugs and replaced the #4 Coilpack
It was a little rusty and nasty. Seems to be running like a top now.
Thanks for all of the advice.
Lake

 

Lakenut, what was the tally on the plugs and #4 Coilpak, dealer or did you do it. Mine 5.4 is acting up too. 1st i thought it was the tranny, but flushed that and its still doing it.