It has 108k on it and just had the transmission rebuilt (2nd gear clutch or something went bad). Anyway- have noticed recently that if I'm going 45 or so with light pressure on the gas or going uphill at slow speed- there is a very noticeable stumble like a misfire if the car is in over drive. Otherwise very smooth in all other gears.

I thought it was a problem with the trannsmission again, but then found a few sites where the ignition coils were problematic. There is no check engine light and before I jump into replacing one or more, just wanted to get some thoughts. Plugs are due to be changed out soon anyway, just didn't seem like a real fun project.

If it is the coil(s), I've run across several manufactures including Standard, which a lot of discount places carry. Any of them good to use or do I have to us Motorcraft?

Thanks
Steve

 

Steve, before you do anything, check for codes. And if those are the original plugs, more then likely that is your problem and you need a new set.

 

Thanks John, yes the plugs are likely original.

How likely is it a code would be stored without the check engine light being on?

Trust me, I would love to find out which cylinder is having an issue and focus on that one. I just dumped a good pile of cash into the tranny, not really looking for another big cost if I can help it.

Thanks again for your input!

 

I changed my plugs at 98K because the truck started running like crap. It was a night and day difference. Yes, you could have a pending code without a CEL.

 

*Might* have a pending code stored. But, if you can find someone with a scan tool that can display Mode 6 data, it will show how many misfires by cylinder, for 1000 revolutions. (I know that the AE tool with the optional Ford Enhancement will display it.)

But as l2race posted, may as well start by changing out the plugs first. No sense in stressing the COPs unnecessarily.

 

I'll see if I can swing by autozone and get it read then, I appreciate your help.

Steve

 

I doubt if AutoZone can read Mode 6 data.

 

Ok, will go for the plugs first. Any recommendations? I had a VW that was very picky about plugs and a Ford explorer that chewed on anything.

 

Motorcraft

 

thanks

 

If the problem persists you may have a problem with the torque converter. Did the trans shop replace the t/c when doing the rebuild?

 

Yes the torque converter was replaced along with
Any other wear items. I grabbed some motocraft plugs, new air filter and some sea foam to run though the intake. Got the filter changed and the intake cleaned, pulled off the driver side coil cover and got a feel for the job. What a pita, they were not designed to be removed often that's for sure. This weekend will be fun. Thanks all for the help.

 

I had the same problem on my 2003 Expedition and went with e-bay COP's from global-automotive. Set of eight was only $65. I researched (after some advice) "Low Grade Misfire". New ignition coils solved the problem and have not had any issues since.

 

Have had the exact same problems for a few years. Finally it. Became so bad it was compromising the performance of the Expedition (2005 model), which I use to tow a fairly heavy pop-up camper. I was actually able to get it to throw a code and took it to an auto parts place to get the codes read. Found a misfire on cylinder #7. Replaced the COP, test drove it and it set a code that didn't go away even though it ran much better.

Back to the auto parts place where the scanner showed a misfire on cylinder 8!! Replaced that COP and it has run great so far.

Interestingly enough I replaced 6 of the 8 plugs about a month ago, even though they had been in there for only 3 years and 40,000 miles. Was able to do 1-4 fine, then broke 5 & 6, both of which I extracted, and decided I wasn't going to press my luck with the last two.....7 & 8! The dealer replaced the plugs a few years back. They reinstalled what I was told were 2 piece Motorcraft instead of the supposedly stronger one piece Champion, which I had already bought, and they didn't anti-sieze either. The 4 I removed successfully came out harder than hell.

If you can get a code to set by driving it hard go directly to an auto parts place and get the codes read without shutting the vehicle off as the code may not stay otherwise.

Good luck!!

 

Just and update, replaced the 8 plugs just to see if that would help. Definitely smoother and Idle is much nicer, but still has a stumble. Ordered the coils and will get them in hopefully soon.

Thanks for all the help. The plugs were a bit tough to break loose and the back 2 were tricky to get to but otherwise no issues.