2004 Cadillac Deville

Engine Performance problem
2004 Cadillac Deville V8 Front Wheel Drive Automatic 95000 miles

i have an 04 deville with multiple misfires. I have replaced the plugs and coil packs, and it got a little better but it still misfires enough not to pass emissions. Any idea's?
April 28, 2009.

If you can determine which cylinders, swap some secondary parts. If the misfires are on 1 bank, swap the coils. Or change plugs of affected cylinders. If the fault stays with the cylinder, you could have dirty/sticking injectors, water in the fuel, or a mechanical problem. A compression and leakdown test would be advised at that point.

Apr 28, 2009.