Need help everyone, going down the road---first off had this baby since 40K and I am at 209,000K 1998 LS400---so, going down the road setting at a light and it starts to idle very rough, begging light to change so I can give it gas I do and off we go a little rough at first---looking for a place to pull in and I do--it quits and will not start---after a few mins I try again and it starts but, wow its making nosie under the hood and running real rough----where I pullled in was autozone so, I get him to pull numbers and I get PO340, P1345 and PO420