knock sensor
I have a 92 s10 blazer and my code 43 was fixed by replacing the knock sensor. so maybe check the knock sensor and the wiring from that to the ECM.
Knock First - 2003 Kimberly L- 2-43 was released on: USA: 2004
code 43 except2.2or2.5 4flashes pause 3flashes electronic sparkcontrol knock sensor circuit probable cause faulty knock sensor or mem_cal.
knock sensor
Electronic spark control is not receiving sinal from knock sensor Try replacing knock sensor
any from 88 to 98
Kachorra - 2002 1-43 is rated/received certificates of: Argentina:Atp
Cinematech - 2002 Tobal No-1 1-43 was released on: USA: 12 September 2002
Cinematech - 2002 5-43 was released on: USA: 12 November 2006
Cinematech - 2002 6-43 was released on: USA: 22 October 2007
About 43 miles or 70 kilometres, and would take about an hour.