Lots of misfire threads but I still have questions

[bob380sx]

Well my CEL came on to day code p0307. The car (02 LS8) had a very brief misfire yesterday maybe lasted 3 sec. The light didn’t come on tell the car was started this morning. The car ran just fine after the brief misfire for the rest of the day and is running fine today. After reading the many topics on LS misfiring I have found it could be a few things. Seems bad coil is the more often the culprit over the other stuff like injectors, plugs, injector plugs, poor compression, oil, etc etc. I also found the #7 cylinder may not be the actual location of the misfire. I’m going to check the injector plugs tonight.

Now for the questions would the fact that this only occurred briefly lead any of you to believe one component is bad over another? The car also has difficulty starting and smells of fuel after it fires but runs fine after it has started don’t know if that makes a difference.

And the main thing. I would like to test the coils myself over paying someone to do it. Are there some values I can test at home with my meter?

And last if it turns out to be the coils what’s the best to replace them with. I would hate to put some crappy after market coils in and have to do it all over again to soon. And is there an upgrade coil like MSD or something?

 

[pektel]

AS far as testing coils with a multimeter... I know you can check primary and secondary resistance from reading a thread on the mark viii side this morning. Here's the copy/paste:


"Set your ohmmeter to the 20000 ohms range. Turn on your meter and touch the spark plug wire terminals on one of the coils with the meter leads. You may get a reading between 5000 to 15000 ohms, depending on your particular model. This checks the secondary resistance.
Set your ohmmeter to the 10 ohms range, and touch the terminal B+ (usually the center prong on the coil pack electrical connector) with one of the meter test leads, and touch the corresponding coil prong on the electrical connector with the other test lead. You may get a reading between 0.3 and 1.0 or more, depending on your particular model. This checks the primary resistance on each coil."



As far as testing voltage (copy/paste from the same thread):


"Sure! Heres how you use a multi meter to test them........ YOU DONT!!!

The pulse is around 30-40K volts. Most meters will not read any where near that. Plus the pulse is so fast that even if you did have a meter that could read that much you still wouldnt see the peak even with a peak hold.

You can test to see if the coil is getting voltage but again you need a fast meter with peak hold. Its uber rare for power to not get to the coil though.

Ford dealers and some better performance shops have one of the $10,000 scaners that hooks to the OBD port and can read each coil to tell you which one is bad and how bad it is. When my car was being tuned they tested mine and showed two very very weak coils and two on the edge. I said screw it and bought 8 new coils.


Anywho, point is you need to have it scanned to see what coils if any are bad. "

Whenever you change a coil, you also need to replace the plug. I would start with that. I have a set of Accel coils in my LS with no issues, but you cannot reuse the coil covers. Some are afraid of water infiltration, although I have yet to experience anything of the sort.

How many miles on your LS? I have a hard start issue sometimes (only when warm. beginning to think leaky injector as well), and my plugs show signs of running lean. But I have 153K on my engine, so a fuel pump is a very likely candidate.

 

[bob380sx]

how many miles on your ls?

150,000