'02 LS V8 rough running.

[Storloc]

I've seen the posts about how the coils get contaminated by either water or oil and cause a misfire. I had the used car dealer replace the plugs and we checked for oil and there didn't seem to be any in the wells. They said they found a bad coil and replaced it, the car ran fine for a few days but started to run really rough again today with the engine light coming on. It's bad enough you can feel the car shake when it misses and can hear and feel the exhaust pop. It also shudders when under load most noticable in 5th gear when pulling a hill. They also admitted to washing under the hood when they got the car for original sale but I can't see how water can get into the coil wells with that cover over them. At any rate is there anything else that can cause this intermittant problem besides coils or plugs or should I just shotgun the 7 remaining coils and see what happens? Almost forgot to mention the car has 50k on it. Thanks in advance guys!

Karl

 

[00ls-sport]

i had 3 bad coils due to the recon dept washing the engine bay. the seal around the coil cover was bad on one side, so the water worked it's way in. i had the dealership replace all 8 coils, plugs, and the 2 coil covers. stupid recon washed it again one day, but no problems. lucky for me because i left on vaca to pa shortly after the wash.

 

[Storloc]

Thanks for that info.

After reading through a bunch of posts here I think I'll get a scanner, a set of tools and some spare coils as a trunk quick repair kit. Although quick might not be an appropriate name. One thing I have noticed is that the coil problem seems to be the only real glaring issue with the LS. On that note is there any particular coil brand that's known to be better than other's? I saw about 4 different coils listed on an online auto parts site ranging in price from $40-$70 each.

Karl

 

[00ls-sport]

oem is best.

 

[HDDave]

I have the same vehicle ('02 LS V8) and yesterday the car started to run a little rough when I left work. It started out intermittently and I drove about 15 minutes on the highway. Under acceleration I didn't notice the stumbling as much as when I was just cruising. Now the problem is very intermittent. Sometimes the car will idle fine, sometimes it's rough. I can drive for 10 minutes and the car seems fine and then it will start to stumble again. the check engine light came on the 2nd time I drove the car yesterday but not when I first experienced the problem.

I guess my question is - when the coil goes, does it go or can it be intermittent like that? I though it might be a fuel filter problem or bad gas so I added a bottle of dry gas but I don't think that was it. I'm afraid of doing damage to the catalytic converter if I keep driving it around misfiring and dumping raw gas into the exhaust.

Do you guys here think it's definitely a coil problem??