: Bank 1/2004 Deville DTS

07-31-10, 11:09 PM
Hey guys. Here again. My 04 DTS is killing me. It's misfiring again I think. Well it's stumbles slightly at idle, in gear. Like a misfire every couple of seconds. It's really not that bad except it keeps making my check engine light come on. Pulled codes and cleared them. But I used a scan tool because the car wouldn't give me a specific cylinder code. The scan tool didnt either. It just said something about bank 1. I shoulda kept track of the code. I just saw Bank 1 and then deleted it. It'll come back on in a day or two. My question is what side is bank 1? Is the the front of the car or towards the rear. I'm guessin its a spark plug. I have 108,xxx miles on the car right now. At 98,xxx I changed out the front plugs, but didnt do the rear. I couldn't get the damn EGR valve out of the way. But I think that with 108,xxx miles on original plugs, they are dying. But if that isn't bank 1, then I have another problem I have to tackle too. I hope that the rear bank is bank 1. I hope... Anyway, any help would be appreciated. Also, some independant shop said they would change the rear plugs for $200. That's IF I give them the plugs. If they supply, its more. I have the plugs, but damn, $200. Seriously?

08-01-10, 10:00 AM
Bank 1 = firewall side; Bank 2 = radiator side.
Changing the rear plugs is an exercise in Yoga, aerobics, magic words, and time,
and I believe the 2004+ has a different coil setup from 2000+ or earlier.

08-01-10, 10:44 AM
Thanks Sub. I'm glad it's the firewall side. If it was the radiator side, it means I'd have some other problems I don't know about. Guess I'll have the shop change the rear plugs. When I tried, I hurt my arm. I have these two metal plates in my left arm and when I hit those on something, it really doesn't feel too nice. I guess I'll just have to suck up the $200 loss. Thanks again!

08-01-10, 01:07 PM
FWIW, With 10K on the "new" front bank plugs, I would go ahead and suck up the $$ to have the shop install a whole new set of ACDelco #41-987 Platinum plugs.

The new plugs come pre-gapped to .050" - and the shop should check the individual (8) coils and their connector boots also.

For reference, does your 2004 have the 4-coil cassettes or does it have a line of individual coils, one on top of each spark plug ? There came a change in late 2003/2004 I think.......

08-01-10, 10:56 PM
Mine has each individual coil over each plug. I think the change was new for 2004. You think 10K miles on the "new" plugs would make a difference compared to the 0 mile ones?

08-02-10, 08:41 AM
Probably no real need to change 10K plugs - I personally would, just to keep a level playing field........
I don't think that's an EGR on top of the rear cam cover - it's usually the Bank 1 AIR valve. Should
be another down by the lower radiator hose - below and in front of the water pump drive pulley.