Doubt it, 4* shouldn't cause any problems. Mine's somewhere around 8*.
That code would turn the SES light on. So, if it's on while your car's running, you may not have reconnected the EST bypass connector.
Or, if the light is off while the car's running and you pulled the code out of the computer with a paperclip or a fancier code-reader, remember that you set a code 42 when you disconnected the EST connector and started your car to set the timing. That code's going to stay there for the next umm.. 50? or so engine starts.
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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else | 
