hk_rogers

Hi Rod,

I pretty much parked it for the winter and just got back into it yesterday. A buddy of mine has a high-end snap on scanner so we hooked it up and voila, cylinder 1 was misfiring like crazy even though the computer showed no code. Go figure. Anyway, replaced the coil and running like new. (BTW it is possible to replace the cylinder 1 coil pack without pulling the intake, just takes a little bit of puzzle solving! Thanks for all the input.

My old OTC Genisys scan tool would be a nice help for you right now. It had a mode where I could monitor individual cylinder misfire counts real time, even if they were not high enough to trigger a diagnostic code. The '98 SHO I had would misfire enough that I could feel it, but never set a code. I was able to track down the offending coils with the Genisys and it found them every time.

If you're really convinced it's a misfire, you could try disconnecting 1 coil at a time to see if you can find one that doesn't seem to have much impact on the way the car runs. When/if you do, you've likely found your offending cylinder. Then check compression on that cylinder, see if the spark plug is wet with fuel. If the compression is good, you might try swapping the spark plug with another cylinder and the coil with yet a different cylinder, then repeat the test of disconnecting one coil at a time to see if the misfire remains on cylinder or follows the plug or coil.

I cannot think of any way the clockspring could cause the car to run funny. Going back to the battery, how old is the battery? Before changing the 3 year old Napa battery in my wife's car, I load tested it with a 100A load and checked the conductance of the battery. Both suggested the battery was "good" but with all the electronics in a modern luxury car, "good" is not always good enough. The first time I ran in to this was on a 1997 Olds Aurora. Two places said the battery was fine, yet it wouldn't even crank the engine over if the headlights were on (which they came on automatically when dark). With a voltmeter on the battery when turning the key to start, we could see the voltage drop below 10 volts. Installed a new battery with no other changes and the car worked fine for the next 2 years he owned the car.

-Rod

Come to think of it, it has had some rough starts recently. It doesn't really make sense but maybe there is a battery issue.

Thanks for the reply. Battery is relatively new (couple of years). It misses at idle, park neutral and when accelerating. It get's really bad between like 30 and 40 mph. I guess i could have the battery checked to make sure. Got me baffled. It really "feels" like it did when the coils had gone bad. I've replaced 2. (Having to do them one at a time as I can afford them ha) I'm going to replace 1 more Junk eBay coil that I bought a couple of years ago and see if that does the trick. If not I'm stumped.

How old is the battery? My wife's 2002 LS would stall just about every time she backed out of the driveway the first drive of the day and shifted to Drive. There were no diagnostic codes and everything seemed fine. I finally replaced the battery and never had another issue with the stalling. Her battery was only 3 years old at the time.