I have a chevy astro 2002 with 140K. I did a tune up after the check engine light went on. The tune-up consisted of sparkplugs, wires, fuel filter, rotor, distributer cap, air filter and fuel injector fuel treatment. The vehicle is now running worse. It misses really bad at idle. Here are the error codes
02 sensor heater
Injector circuit open
Random multiple misfire
Evap. Emission control system range
What does all this mean? Why did this all happen at once?

Help is greatly appreciated.
Thank

Not in any particular order:

What does all this mean?

What it means is that something changed to cause the PCM to think that an injector circuit is open. That could be a failed injector solenoid, poor connection, or failing PCM.


Why did this all happen at once?

Failures don’t often occur gradually.


I did a tune up after the check engine light went on.

While a tune up is not a bad idea, the parts you replaced did not address the failure (obviously). What you did is tantamount to replacing a headlight bulb in an effort to repair a flat tire.

If there is a failed injector, liquid fuel injector treatment is not going to rewind an open injector solenoid coil, nor repair a failed injector pod electrical connector on the CPSI unit. You need to diagnose the problem with the hints given by the PCM and identify the cause.


It misses really bad at idle.

That would be a symptom of a failed injector or incorrect mixture.


Injector circuit open
Random multiple misfire

A failed injector would cause a misfire. A failing injector pod connector could cause a random (not specific to a particular cylinder) misfire.


02 sensor heater
Evap. Emission control system range

These may be unrelated, or may be indicative of an electrical system connection problem related to all the symptoms. You need to study the schematics for the powertrain control and determine if a single connector or device is common to all these circuits.