how to fix po307

Question

my 2004 cadillac deville has code po307,i have changed the entire bank of coil packs,replaced intake manifold gaskets,spark plugs,but still have this darn code and car runs but runs rough.

Answer 1

Hi there,

I would do a compression check on cylinder 7. Its possible there is something wrong inside the engine causing the code. A bad valve or compression rings could be causing the misfire. Take the compression on that cylinder and with a couple of the others for comparison.