I recently had my check engine light come on my 1989 305 tbi Iroc z camaro 5 speed manual. I used the paper clip method to find out its a code 43-Electronic spark control. It only comes on after awhile driving. it seems like it will come on when the car is lugging under a load in a higher gear. when it does come on the engine is doggy. I shut it off and start it again the check engine light goes off and seems to run fine.

So where do i start?

Knock sensor?

Ive been running 91 octane premium gas ( I have also read that a higher octane gas will throw it off too, dont know if that is true)

thanks

 

Found this explanation regarding code 43.

CODE 43
Trouble Code 43 indicates that there may be a malfunction in the Electronic Spark Control (ESC) circuit. ESC is used to sense spark knock (pinging) and retard the timing to eliminate it. The knock sensor is located at the rear of the engine block. The ECM will retard the timing by as much as 20 degrees in 1 degree increments. A loss of knock sensor signal or loss of ground at the ESC module will cause the signal at the ECM to remain high. The ECM will act as if no knock is present, and
may possibly result in engine damage, due to detonation.
Code 43 is set when:
? Voltage at Knock Sensor is above 4.8 volts or below .64 volts.
? Either condition is met for about 10 seconds.

Hope that helps.

 

Thank you! I will give the knock sensor a try