: questions about PC0300 code on 96 deville

12-12-07, 11:05 AM
Guys, I got a PC0300 code on my 96 deville. The first thing I wanted to change is spark plug wire. I purchased Acdelco wire set (#748J) from Rockauto. On the Rockauto website, it says this part is for replacing GM part 12192049. But on the package I received, it says this part (same Acdelco #748J) is for replacing GM part 19172242. Anyway, I put the new wires on, but the same code still came again. I think I might put the wires in wrong order because 1) the old wires on my car are not original ones (I have them replaced by somebody two years ago), so they are not labelled; and 2) the lengths of the new Acdelco wires are different from the old ones on my car. Here are the lengths of the wires I put on for each cyclinder:
1#: 28 inches
3#: 22
5#: 16
7#: 20

2#: 40 inches
4#: 40
6#: 40
8#: 36

I have three wires with the same length (40 inches). Is it normal?

Please let me know if I put these wires in wrong order.

Also, please let me know what else I should consider to change.

Thanks a lot.

12-12-07, 12:54 PM
P.S. This happened just after I changed oil. I recalled that I accidentally added a little bit more oil than required (about 7.8 versus 7.5 quarts). Is this the reason why I got such a code? Thanks.

12-12-07, 04:54 PM
No. overfilling the oil will not set a DTC.

Do a search for firing order. It may have been posted before.