Chevy truck k1500 4.3 runs bad

the lamp means 2 things CEL (SES/MIL)
it means there is a serious problem.
it means get car service
if frisky? it means DIY scan the pCM and check all fuses.
SES lamp is what some makers of cars call the CEL
it means exactly the same thing.
lost the glove box free users guide it tells you all this.
not many 89 cars on the road now, most are dead
and repairs exceed its value (won't stop me but, most end here)

89 Chevy Cheyenne C1500 pickup truck,.
no engine told. generation 4 truck.
4 engines then, 4.3v6,5.0v8,5.7v8 , 6.2Ldiesel-v8

finding 1989 manuals is hard, only paper manuals then no PDF or others doing horrible scans later,
the problem is this cars ECU/ECM/PCM is chevy OBD1 system and there are flash codes (cel /ses ) blink codes for error huge.
if the CEL glows it means 99% of time a major error
like dead sensor , 100% dead,
4.3L has distributor and horrors of TB throttle body injection TBI. not MPI we have now.
5.0 same thing
5.7 -same
diesel ? ask. rare option. for sure running at all.

gasoline engine surge has many causes
i will list some only
spark bad.
fuel injectors messed up. 2 there are.
fuel pressure out of spec, FPR bad.
IAC DEAD OR JUST DIRTY.

NOW THE FLASH CODE OBD1 MAGIC
jUMP ALDL , PIN A TO B.

https://mechanicbase.com/trouble-code/obd1-codes/

ok lets start with the codes they say your getting. P??? which 1's and how many. there are few o2 sensors, are they next to the Exhaust next to the converter? MASS AIR FLOW -MAF use this, for now i am guessing, until i see the correct codes your are getting. this could be the 1 you may have below, please read it........

• P0103
  Mass Air Flow Sensor Circuit High Input
• Possible causes
• Faulty mass air flow sensor
  - Intake air leaks
  - Dirty mass air flow sensor
  - Dirty mass air filter
  - Mass air flow sensor harness is open or shorted
  - Mass air flow sensor circuit poor electrical connection
• Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner. Reset code and drive vehicle. If the code comes back, it may be necessary to replaced the mass air flow sensor.
• possible symptoms Engine Light ON (or Service Engine Soon Warning Light)
  - Engine stall
  - Engine running rough
  - Excessive fuel consumption
  - Excessive smoke
• the code is generated when An excessively high voltage from the sensor is sent to Engine Control Module (ECM).

2003 NISSAN Altima Sedan OBDII Codes List

Check for loos connections between the intake and the tube from the air filter. Check if the clamp is loose or leaks in the tube which can cause an incorrect reading. Other than that it may be a dirty MAF sensor which can be fixed by spraying carb cleaning or tuner spray in the intake or it may be bad or a bad oxygen sensor;.

It sounds like a bad fusible link. Hard to say where it is. Could be near the starter solenoid or the fuse box under the hood.

Hey One, Sounds more like the fuel pump...just my 2 cents worth...
Chevrolet 1500 1988 1998 Repair Manuals

Chevy Service Manuals Original Shop Books Factory Repair Manuals

The mass flow sensor on the 1998 Blazer is along the intake tube right after the air filter intake housing. Loosen the two clamps that hold the MAF sensor between the Air filter box cover and air intake tube, disconnect the wire leads at the MAF sensor connection and remove the MAF. Note it's uncommon for the MAF sensor to go bad and 95% of the time, cleaning it with MAF sensor with MAF cleaner will fix any problem it may of had to trigger the DTC codes.
Start with trying to clean it first just by following the instruction on the MAF cleaner. This should save you time and money to get your Blazer running 100% again soon.
Good luck and thank you for using Fixya.

If it has been serviced correctly just take it aback and ask them to reset the warnibg light. If they can't then you should chose another garage to service it.

most any sensor going bad can cause the check engine light to come on,try disconnecting the posative battery cable for 15 seconds ,then put it back on,will reset the codes, or take it to auto zone,they will test your computer for codes at no charge to you.i had a venture van my was ox. sensor. thanks robert b.

the 2 codes are

P0134 02 Sensor Circuit no activity Detected (bank 1 sensor 1)
first check your fuses check the wiring to the sensor(the sensor is on the exhaust in front of the engine-open the hood and look down) if the fuses and the wiring look good replace the O2 sensor there are 2 types of sensors original equipment(oe) style and universal the oe style has a connector you just plug in, the universal you have to hard wire in

the 2nd code is Mass Air Flow (MAF) Circuit Low Input
check the wireing, make shure theres a good connections
you said that you already replaced this sensor so im going to recomend that you go after the other code first

deal with the oxygen sensor then reset the computer and see what codes come back