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88' TBI - Code 42 Help

Charleshugh

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Joined
Aug 31, 2022
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Location
North Carolina
I'm throwing a code 42 on my blazer and need some help.
Background; I drove it to a neighbors house and when I went to leave I was stuck with a crank and no spark condition - we then sent it to the shop where they replaced the distributor. I got it back and it had an engine light (I'm guessing it was also a 42), I drove it for a week while it acted pretty sluggish and didn't idle right and now it starts but will cut off when I give it any gas whatsoever.
After seeing all of the other forums on this I know it can be caused by a lot of different issues so I'm not too sure where to go from here?
If a distributor is bad out of the box can this throw that code? Would a bad distributor even allow my truck to start?
 
code 42 only sets if the EST or bypass wire are open, grounded, or if they see unexpected voltage.

constant code 42 - open/short in EST or bypass (wire or connector). bad ICM. bad ECM.

intermittent code 42 is from unexpected voltage on EST or bypass - plug wire on ICM or sensor wire (EMI). bad plug wires with cracked cover (volt leakage). cracked distributor cap (volt leakage). loose rotor under cap(volt leakage). Cap with a bad terminal (volt leakage). wiggle the ICM harness and the bypass harness to check for a bad connection or a rubbed through wire.
 
Start by moving the spark plug wires away from the small wires to distributor and coil.

The high voltage in the spark plug wires can mess with the ICM signal to computer.

Did the "new" distributor come with new cap and rotor? If not they need to be inspected for carbon tracting and cracks,
 

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