Lately my 87 IROC has been throwing a code 43 occasionally. This only happens when I bury the pedal and it hits around 70 to 80 mph. I took the plug off of the knock sensor and it was corroded, so I wire brushed it a bit and it seems to be like new now. I reconnected of and took it for a drive. It still threw the code when I went to 70 or 80 at WOT. I will scan it tomorrow and I also have a voltimeter so I can check wiring ect.

I guess my main question is: is there a reason it is only throwing this code at WOT to 70 or 80 mph? I haven't heard of this before.

 

Bump

 

my GUESS would be that the timing is going out of the operable range at those RPM's. when the ecm faults it reverts to base programing causing it to enter "limp" mode.

 

Update: Everthing seemed normal on the scan. I swapped out the knock sensor and the car has been running a lot stronger. No codes since I swapped it.

However, I've also put a new distributor in and fixed some vacuum leaks along with a few small adjustments (ac delete, smog delete, air foil, new ex. Manifold gaskets, some Lucas oil)