dtc's on obd2 Need help understanding.
I have just finished a 37 ford fiberglass street rod with a 6 liter engine and automatic trans.out of a 06 GTO 6000 miles. The wiring harness is from street and performance. The computer has also been reworked by them. My question is, I have a check engine light on and after scanning the trouble codes one being po174 system to lean. (Possible fuel injector restriction ) The second code po690 has me stumped ecm/pcm power relay, sense circuit Hi. If anyone can shed some light on this I would appreciate the feed back.