I have a 97 espy and it has been missing for awhile the check engine light hasnt come on yet. I replaced the spark plug boots and it ran perfectly for about 300 miles and then it continued to miss. I havent come up with anything else yet maybe thinkin it could be the egr valve but im not too sure. anybody got any info that they could share would be greatly appreactiated. Im at a total loss as what is could be.

Thanks
Don

 

My wife just started experiencing the same problem: Misfire when engine is under load, going uphill in overdrive is when it is most noticeable. No Check engine light came on and I tried to make it come on today without success. We have 5.4 l with 88000 miles and I had the #4 coilpack replaced about 6 months ago and I paid a fortune (just under $270 for diagnostics, labor and parts) to have that coilpack replaced because I did not have the time. The mechanic at the shop told me to think about replacing all the coilpacks as when one fails its only a matter of tiem before the others fail. I have a few vacation days right now and I'm wondering if I should replace plugs at this time and with ohmmeter test each coilpack. My manual indicates .55 ohms for primary side and 5500 ohms for the secondary side. Any comments?

Is there an aftermarket coilpack that is better than others? I would prefer one with a lifetime warranty if available.

Also regarding plugs, I want to stick with OEM plugs. Are Motorcraft and Autolite the same? and could someone provide me with the correct plug number for my Expedition?

Thanks in advance

 

Look up the correct Motorcraft replacements at www.motorcraft.com Autolite makes excellent replacements and they are the OEM for Motorcraft. While the plugs are not "exactly" the same, they're so close that you can't tell the difference.

Replacing all 8 coilpacks will run your over $400 in parts (AutoZone) and a day's work. Highly expensive but it's your time and money. Your mechanic must have a boat payment coming due...

A GOOD scanner can access the misfire monitors and can show the cylinder('s) involved without a CEL.

Steve

 

projectSHO89,

Thanks for the info. Can you provide an example of a scanner that is capable of reading the misfire codes without CEL?

 

so i should replace the coils? try it and let me know what happens

thanks

Don

 

Truckin4life,

At what rpm and conditions are you experiencing the misfire?

Today, I took a trip with mine and while driving uphill several times, I could make it hesitate between 1300 and 2000 rpm with trans in overdrive going uphill and stepping on accelerator just enough so that trans. would not downshift. At higher speeds and rpm there was no hesitation under similar conditions. Even though it was raining most of the day here, the hesitation was no worse today than previously.

 

98... your problem sounds like the OD on a border line downshift. Mine does it too. You will find that the trans will attempt to down shift but doesn't have all the right conditions to do so. If you give it just a hair more throttle it will downshift and not give you that hiccup feeling. You have to remember... this is a HEAVY vehicle. It will downshift going up hills just to pull it's heavy **** up the hill. This is not uncommon.
As for the other miss... Does it miss while idleing? If not what RPM does it miss. I chased a miss in mine for three days. I got all kinds of codes pop up in those three days ranging from the O2 sensors to the crank angle sensor. I bought one coil pack and went back to basics. I let the truck cool down and then started it and unplugged one coil at a time until I found the one that med no difference in idle quality. I then changed that coil. I also have a small handheld scanner that was very valuable in diagnosis of this problem.It is an Actron Pocket scan. It will scan everything from 96 up. If you have OBD II you need to get a scanner. THis one was only $80 and it works great. It reads pending codes as well as stored codes. Plus it allows you to erase codes. I eventually made mine throw a code by driving it hard... extreme acceleration uphills and it finally threw a code for cylinder 3 misfire. I changed that coil and no further problems. My Expy has 181,000 miles on it and I would drive it anywhere! One alternator replacement at 150,000, 2 sets of brakes, one pulg change, one coil pack. Reg maintenance... oil and filters, and fluids..... no problems. Have patience and use basic skills on diagnosing the problem and you will get it repaired.

 

sounds like great advice from 4by4. i had a coil go out about a year ago and thought it would be covered by extended wty but to no success. i had a similar bill to the original poster.....nearly $300. This is crazy I told them. these things look like they just simply plug in and that's all there is to it. Is it really that simple or is it more involved than this. btw......my mechanic must be an honest one because when i aksed if it was necessary he told me that it would make no difference whatsoever in anything and to wait for the next one to go out before replacing it.