i was having a code 300 multi cyl misfire i was also having a catylst inefficiency code do not remember code. i replace cats and that stoped and now this started almost right after. i forgot to list, when started first thing in the morning and i go to leave, it falls on its face like an old carburated car would back in the day. i replace fuel pump last summer the wires to the plug melted so i did the whole thing. and yes i used all ac delco stuff. i have not checked cam retard. im starting to think i have a sticky valve or maybe new injecter failing. im not sure. im tired of spending money chasing the ghost!! any other ideas would be great. as for sunday thats just another work day here
. thanks. mark.