I have 1990 corsica 3.1L with 29k miles and it is throwing a hard code 42. It runs rough and idles too high when slowing down. When it comes to a complete stop, it finally kicks the idle down and almost dies.
I have replaced the following so far.
I have checked these wires for continuity at both ends.
-#450 to ground
The SES still comes on after a few seconds of idling. I am wondering if the plugs, wires or coils would make it throw this code? I did check the coils at the secondary pins and I had something like 5.8#, 5.8# and 5.9# ohms.
I'm not sure what else to do and getting tired of spending money on non-fixes.