the reader picks up a po303 only after a long period of idling.the first o2 sensor reads .1 to .7.
Buick Q&AAsk Your Question
1999 Buick LeSabre Question: code po303...what would I expect the o2 sensor to read if an injector is leaking
Answer #1pushrod September 06, 2013, 16:01Master
This code indicates a misfire on # 3 cylinder! Possible ignition fire, fuel injector or low compression. Forget about anything else until this is repaired!!
Replyglenn sr, September 06, 2013, 16:56Rookie
new wires, plugs. ohms correct in wires...plugs gapped @ .065 haven't checked compression
Answer #2ebans777 September 06, 2013, 16:35Journeyman
agree with pushrod
Replyglenn sr, October 26, 2013, 12:21Rookie
here's where the problems stands...new spark plugs and wires. compression good, new coil, had a scan run and was assured that the injector was bad, replaced injector..PO303 still comes on at idle. I wiggled the wire at #3 injector and that seemed to work. I soldered in a new #3 injector plug in and wire. latest result is.....PO303