Recently my wife's 99 Expedition 5.4 Triton started running rough. Found a bad coil pack and replaced it which made it a little better. Decided to replace all the plugs because it had been a while since the last replacement and that seemed to do the trick for a short period of time. Now whenever it feels like it, the engine runs fine under load and idle, but sometimes (more when the engine is at operating temperature) it starts to misfire but never dumps a code. Also I've noticed that when you go to start the engine, if you put the key in and try to start it immediately, the engine won't start; but if you wait until all the electronics and guages power up (about 5 seconds) the engine will start. I'm thinking the fuel pump is going out but I'm not sure. The fuel filter has been changed recently. I have a SCT X3 tuner for my 07 Mustang that will do data logging and was looking at some of the logging features the other day. I know I can monitor fuel pressure among other things with the X3 but don't know what the proper values should be. Any ideas of what I should monitor and what values I should be looking for? I'm well aware of the COP problems and have already replaced 3.

 

can you log FPDC (fuel pump duty cycle)

1st before anything id change the fuel filter if it hasnt been done in a while.

 

Replace ALL the cops - they are less than 100 bucks for a whole set from Global on Ebay. If you did not use Motorcraft plugs, order up a set of those too. Autolites and Bosch don't work worth a crap in a Triton.

 

I wouldn't worry about the fuel pump. If you immediately turn the key and go to start the pressure hasn't built up in the fuel rail. To be sure you can check what the fuel pressure is at the rail. My 2001 would do this if I didn't let the pump run a few seconds before hitting the starter. I think you are fine in that area. I have seen this on more than one truck...
As far as the miss fire, It sounds like a winding in the coil is breaking down due to the heat. I have seen this before. Sounds like a coil issue to me....

 

When the cops start to go, they are all now suspect. It's also common to get a brand new cop that has issues. That's just the way it is, and to me it makes sense to pay the same amount for all 8 than the cost of 2 at the parts store and one at the dealer. The Globals have a warranty, if any are bad they will replace them, and you will have the ones you pulled as spares, a few of them will still be good.

Make sure you use enough dielectric grease.

 

I'll probably do the COP replacement soon if its less than $100. Just bought the SCT X3 and it set me back a bit. Was trying to get throttle lag out of my 07 Mustang when the Expedition started acting up. I will look at fuel pressure duty cycle and see if it will log that data. I have been logging and monitoring the load and spark as well but I'm not too sure what the values mean. Seems like you can never have all of them fixed; Bronco has ABS failure - coil failure in the module, vacuum leak somewhere before the firewall, and really bad gas mileage despite the sixlitre tuneup. One of these days I'll get them all fixed...........maybe.

 

What did you put in the Expy for plugs?

Here's the cops - 87 bucks shipped, lifetime warranty:

http://cgi.ebay.com/NEW-IGNITION-COI...QQcmdZViewItem

 

It was the Motorcraft Platinum plugs. They had been in there for about 4 years and when it started missing, I replaced a bad coil $65 and the plugs.

Thanks for the link. I'll check it out.

 

Hey I've got a similar problem. I replaced plugs and cops (from Global) 4 or 5 months ago, and fuel filter within the last week. Around 45 - 55mph the truck will start bucking and studdering a bit. If I let off the gas or accelerate, it'll go away. Also this doesn't happen in overdrive, and the truck hasn't given me codes since I replaced the plugs/cops months ago.

Anyway, if this is indeed cop related, is there an easy way to tell which cop it may be so I can exchange it with Global and use their warranty or do I need to do all 8?

 

You have to troubleshoot by substitution - you did keep the old cops, right? You did use enough dielectric grease in the boots?

 

Thats when I purchased my COPs from Global and I am haveing the same issue. I am starting to think the had a bad batch. I have my old ones and I am going to try a one by one replacement.

 

I stand corrected. I just checked my codes and have a #4 misfire but no engine light.

Update

It was the COP so now I get to contact Global for warrenty.

 

I had kept them for awhile, but I just moved, so I think I may have thrown them out with a bunch of other trash. I'll see if I can't maybe get codes pulled even though there isn't a light on.

 

Did this show up as a pending code on your scanner, but didn't trip the CEL ?

 

I have the COPs on the way. In the meantime I found the PCV hose between the plastic tube and the vacuum tree at the intake collapsed again. Replaced it with some reinforced fuel line instead of that cheap rubber it comes with. Have not driven it but wife says it is still missing. I put my XCAL on it and was doing some data logging but I don't really know what to do with the data. I need to put my MacBook in there and connect it to the XCAL and drive around for a while. Anyway check that PCV setup and see if any of the hoses collapsed between the intake and the PCV valve.