stutter at highway speeds

[yeah61794]

Hi all, I finally got my 93 licensed and insured so now its drivable. I noticed one thing though; when on the highway it will stutter about every 15-20 seconds. It subsides immediately when I let off the gas. It not a major stutter and not noticeable at any other speed, but still a concern nonetheless. It also has a rough idle, which I really do not care about unless the two are related. The best way to describe it is like you are going over a very small bump on the highway, except this happens when there are no bumps. Thanks

 

[Joe Dirt]

Has the fuel filter been changed?

Also- check the plugs/wires. You could be arcing enough to get a hesitation.

 

[dogfriend]

Misfire under load. Try driving up a hill at highway speed and see if it does it to confirm.

Mine would do it towing a trailer or driving uphill. I ended up replacing the coil pack. You should try plugs and wires first, that is cheaper and might solve the problem.

 

[yeah61794]

Sorry I never said, I just changed the plugs and wires because it looked like they were still originals, the fuel filter looks brand new as do the lines, the rest of the vehicle had a lot of rust on it and the fuel filter and lines were spotless, so I think the previous owner had new lines put in and a new fuel filter at the time. I have a fairly large hill I can drive up and it just seems to do it at highways speeds, the load doesn't seem to matter because the frequency or intensity does not increase going up the hill.

 

[dogfriend]

Here is a thread on testing the coil pack

http://www.explorerforum.com/forums/showthread.php?s=&threadid=96320&highlight=coil+pack

I would test to see if the resistance of the secondary side of the coil(s) is below 11,500 ohms or not.

 

[JTH1972]

the fuel filter looks brand new as do the lines, the rest of the vehicle had a lot of rust on it and the fuel filter and lines were spotless,

I'd replace the fuel filter anyway just to be sure. The fuel filter looked new on mine when I got it, but when I finally got around to pulling it off, the insides of the filter rattled! You just can't tell by the outsides.

Also, one thing I've learned, is pull your battery cable off for 20 minutes or so and reset the computer. Your Ex will drive totally different.

 

[yeah61794]

Ok guys, sorry for the delay, been busy with school but here is an update. I drove it out to school and back on the interstate, didn't stutter at all. Only seems to do it around about 40-60mph. I tested the coil pack, every bank was 13.76k ohms, with one exception being at 13.56k ohms. I have not tried replacing the fuel filter but I have reset the computer and nothing. I pulled all the codes and everything came up all clear.