my 99 catera cadillac- codes po300,po303, and po305-- were determined to be an issue-- what is the likely cause.

Question

what is the likely cause of all the above codes- spaerk plugs or injection system-- could it also be the fuel filter.???

Answer 1

Hi there,

The most common issue would be the plugs, wires or ignition coils. The injection system would not be as common for more then one cylinder. As for the fuel filter, if it were the issue it would affect the whole engine and not just these 2 cylinders. It's likely you have a problem with the ignition coils.