ok,ive been fighting a code 42 for the longest damn time...

tons of troubleshooting....the only time i saw promise,was when i put in a new knock sensor...that worked for all of 3 days,and bam...a WOT run and the 42 comes back on.

quick recap,after extended WOT runs{1/4 mile passes},my car would trip a code 42 fault at esc circuit,or knock circuit...aparently it does a forced knock test during WOT,well seems my car failed it,so it tripped the ses.

anywho....tons of continuity test on the wiring,checking ohms of the KS....nothing fixed anything,except when i put in a new knock sensor...but that lasted 3 days.

well,i got ahold of a full exhaust system,ceramic coated headers,y pipe with cat delete,and aftmkt catback.....i installed all of this....been driving the car now for some time,and ill be damned if the code 42 is gone....i cannot for the life of me get it to come back,normally it would set when i shifted into 4th gear,sometimes 3rd. i have done multiple high speed runs to 150 and it WONT set.....how in the hell is this possible??

car is an 88 iroc 305 tpi 5 spd.

 

Possible loose exhaust banging against body (been there) fixed when you replaced the exhaust.

 

WTF!!! so i had the same problem but after replacing the ignition module and coil it went away for a day now its back but when i gun it it goes away...possibly knock sensor related?????????? Ive been messing around with this thing for over a week now and still havent been able to figure it out