Check engine light stays on. changed oxygen sensor, pcv valve, coolant sensor, switched out PROM chip, and cannot get a code to blink. replaced all hoses coming off carb. smog pump and egr valve been removed years ago. this problem just started a few weeks ago. carb about 5 years old rebuilt. any ideas on what else to try???

You replaced all four 02 sensors ? Why ? It's important to note here, the very nature of the oxygen sensor sending these codes, without any other oxygen sensor fail-codes tells us the sensor is working as it should. What makes this code tricky is if this code appears by itself, there is NOT a monitored component that has failed, or it would be getting a code as well. In short, the engine is running lean, but the computer cannot tell why.
You replaced all those parts ? Time to take it to a qualified repair shop , because you have no clue an without the vehicle infront of use to test we don't either , especially after you replaced all those parts . Doing fuel pressure testing , hooking up a professional scan tool an viewing fuel trims (long &short term trims ) So do yourself a favor .

SAE J2012 Revised DEC2007 lists Diagnostic Test Code (DTC) P0133 as "O2 Sensor Circuit Slow Response Bank 1 Sensor 1"

This code basically means that the upstream oxygen sensor on bank one of your engine is not responding as quickly as it should to changes in oxygen leavels in the exhaust.

The usual causes of this is an oxygen sensor that is just plain worn out (if it has a lot of miles on it) or an oxygen sensor that is contaminated by engine oil or antifreeze leaks causing these fluids to be burned in the exhaust (like bad piston rings, defective PCV valve, blown head gasket, etc.).

In any case, the oxygen sensor needs to be replaced. However it should be noted that if it is caused by contamination like that described above, replacing it will only result in a new oxygen sensor doing the same thing if the cause of the contamination is not repaired.

P1131 Lack of Upstream Heated Oxygen Sensor Switch Sensor Indicates Lean...

P1132 Lack of Upstream Heated Oxygen Sensor Switch Sensor Indicates Rich...

check the gasket for the bottom of the intake plenum
to check remove pcv valve from the valve cover plug the vent hose from the other valve cover and the hole the pcv valve was removed from with your fingers while the engine is idleing. if it builds up a vacuum, noticable by a air rush sound when you remove finger from vent/pcv grommet hole then the gasket for the plate on the bottom of the intake plenum has blown out. it is a very common problem and results in fould plugs and oil consumption problems.

CODE 12- NO DISTRIBUTOR REFERENCE PULSES ECM. CODE 13- OXYGEN CIRCUIT. CODE 14- COOLANT SENSOR HIGH TEMP CODE 15- COOLANT SENSOR LOW TEMP. CODE 21 - THROTTLE POSITION SENSOR VOLTAGE HIGH.CODE 22 - THROTTLE POSITION SENSOR VOLTAGE LOW.CODE - 23 MIXTURE CONTROL SOLENOID.FOR CARBURETOR ENGINE. CODE 24 -VECHICLE SPEED SENSOR. CODE 32 - BARO CIRCUIT LOW.CODE 32 - FUEL INJECTED EGR VALVE VACUUM SWITCH SHORTED TO GROUND.OR EGR VALVE SOLENOID CIRCUIT OPEN. CODE 33 - MAP SENSOR.CODE 34 - VACUUM SENSOR OR MAP SENSOR.CODE 35 - IDLE SPEED CONTROL. CODE 41 - EST CIRCUIT. CODE 42 - ELECTRONIC SPARK TIMING.CODE 43 - ELECTRONIC SPARK CONTROL UNIT. CODE 44 - LEAN EXHAUST.CODE 45 - RICH EXHAUST. CODE 51 - PROM OR MEM CAL.CODE 52 - CALPAK. CODE 53 -EGR VALVE CARBURETED ENGINE THE EGR VALVE VACUUM SENSOR HAS RECEIVED IMPROPER EGR VACUUM. CODE 54 - M C SOLENOID CARBURETED ENGINE MIXTURE CONTROL SOLENOID SHORTED OR FAULTY ECM.CODE 54- FUEL INJECTED ENGINE FUEL PUMP VOLTAGE IS LOW.CODE 55 - ECM MAKE SURE PCM GROUND CONNECTIONS ARE TIGHT.IF OKAY.REPLACE THE ECM.

It is either your Vehicle Speed Sensor (easy to change) or your Automatic Transmission Computer (capacitors burn out on these boards, there is a fix for this too, the picture is at the bottom of this page). You need to diagnose by removing the lower right plastic kick panel on the passenger side. There you will find a blue plug. With the car OFF stick a paper clip, wire or stuff the plug with foil to make electrical connection so that the two terminals are touching. Then, turn the ignition to ON (not enough to start it though, just power it up). When you do this, count the blinks in the "D Light" or count your blinking Check Engine Light. Both are different but can refer to different things wrong with your car. A long blink is the first number and the short blinks that follow are the second number.
So imagine this as being 14 : ___ _ _ _ _

Below is a decoding chart:

The first section will be the check engine light codes, the next one is the Transmission Control Unit Codes read from the D Light;

1 O2A - Oxygen sensor #1
2 O2B - Oxygen sensor #2
3 MAP - manifold absolute pressure sensor
4 CKP - crank position sensor
5 MAP - manifold absolute pressure sensor
6 ECT - water temperature sensor
7 TPS - throttle position sensor
8 TDC - top dead centre sensor
9 CYP - cylinder sensor
10 IAT - intake air temperature sensor
12 EGR - exhaust gas recirculation lift valve
13 BARO - atmospheric pressure sensor
14 IAC (EACV) - idle air control valve
15 Ignition output signal
16 Fuel injectors
17 VSS - speed sensor
19 Automatic transmission lockup control valve
20 Electrical load detector
21 VTEC spool solenoid valve
22 VTEC pressure valve
23 Knock sensor
30 Automatic transmission A signal
31 Automatic transmission B signal
36 traction control found on JDM ecu's
41 Primary oxygen sensor heater
43 Fuel supply system
45 Fuel system too rich or lean
48 LAF - lean air fuel sensor
54 CKF - crank fluctuation sensor
58 TDC sensor #2
61 Primary oxygen sensor
63 Secondary oxygen sensor
65 Secondary oxygen sensor heater
71 random misfire cylinder 1
72 random misfire cylinder 2
73 random misfire cylinder 3
74 random misfire cylinder 4
80 Exhaust Gas Recirculation insufficient flow detected
86 ECT Sensor (Engine Coolant Temperature) circuit range / performance problem
90 Evaporative Emission Control System leak detected in the fuel tank area
91 Fuel Tank Pressure Sensor low input
92 Evaporative Emission Control System insufficient purge flow

TCU Codes:

CODE LIST:

1-Lock-up solenoid 'A' circuit open or shorted.
2-Lock-up solenoid 'B' circuit open or shorted.
3-Throttle Position Sensor circuit open or shorted.
4-Vehicle Speed Sensor open or shorted - No signal from speedometer.
5-Shift Lever Position Switch circuit shorted.
6-Shift Lever Position Switch circuit open.
7-Shift Solenoid 'A' circuit open or shorted.
8-Shift Solenoid 'B' circuit open or shorted.
9-Counter shaft or transmission speed pulse generator open or shorted.
10-Coolant Temperature Sensor open or shorted.
11-Engine RPM (Ignition coil signal) open or shorted.
12-(No code 12 used)
13-Main shaft speed pulse generator open or shorted.
14-Linear (line pressure control) solenoid open or shorted.
15-Kick down switch circuit shorted.

It is either your Vehicle Speed Sensor (easy to change) or your Automatic Transmission Computer (capacitors burn out on these boards, there is a fix for this too, the picture is at the bottom of this page). You need to diagnose by removing the lower right plastic kick panel on the passenger side. There you will find a blue plug. With the car OFF stick a paper clip, wire or stuff the plug with foil to make electrical connection so that the two terminals are touching. Then, turn the ignition to ON (not enough to start it though, just power it up). When you do this, count the blinks in the "S Light" or count your blinking Check Engine Light. Both are different but can refer to different things wrong with your car. A long blink is the first number and the short blinks that follow are the second number.
So imagine this as being 14 : ___ _ _ _ _

Below is a decoding chart:

The first section will be the check engine light codes, the next one is the Transmission Control Unit Codes read from the S Light;

1 O2A - Oxygen sensor #1
2 O2B - Oxygen sensor #2
3 MAP - manifold absolute pressure sensor
4 CKP - crank position sensor
5 MAP - manifold absolute pressure sensor
6 ECT - water temperature sensor
7 TPS - throttle position sensor
8 TDC - top dead centre sensor
9 CYP - cylinder sensor
10 IAT - intake air temperature sensor
12 EGR - exhaust gas recirculation lift valve
13 BARO - atmospheric pressure sensor
14 IAC (EACV) - idle air control valve
15 Ignition output signal
16 Fuel injectors
17 VSS - speed sensor
19 Automatic transmission lockup control valve
20 Electrical load detector
21 VTEC spool solenoid valve
22 VTEC pressure valve
23 Knock sensor
30 Automatic transmission A signal
31 Automatic transmission B signal
36 traction control found on JDM ecu's
41 Primary oxygen sensor heater
43 Fuel supply system
45 Fuel system too rich or lean
48 LAF - lean air fuel sensor
54 CKF - crank fluctuation sensor
58 TDC sensor #2
61 Primary oxygen sensor
63 Secondary oxygen sensor
65 Secondary oxygen sensor heater
71 random misfire cylinder 1
72 random misfire cylinder 2
73 random misfire cylinder 3
74 random misfire cylinder 4
80 Exhaust Gas Recirculation insufficient flow detected
86 ECT Sensor (Engine Coolant Temperature) circuit range / performance problem
90 Evaporative Emission Control System leak detected in the fuel tank area
91 Fuel Tank Pressure Sensor low input
92 Evaporative Emission Control System insufficient purge flow

TCU Codes:

CODE LIST:

1-Lock-up solenoid 'A' circuit open or shorted.
2-Lock-up solenoid 'B' circuit open or shorted.
3-Throttle Position Sensor circuit open or shorted.
4-Vehicle Speed Sensor open or shorted - No signal from speedometer.
5-Shift Lever Position Switch circuit shorted.
6-Shift Lever Position Switch circuit open.
7-Shift Solenoid 'A' circuit open or shorted.
8-Shift Solenoid 'B' circuit open or shorted.
9-Counter shaft or transmission speed pulse generator open or shorted.
10-Coolant Temperature Sensor open or shorted.
11-Engine RPM (Ignition coil signal) open or shorted.
12-(No code 12 used)
13-Main shaft speed pulse generator open or shorted.
14-Linear (line pressure control) solenoid open or shorted.
15-Kick down switch circuit shorted.

It is either your Vehicle Speed Sensor (easy to change) or your Automatic Transmission Computer (capacitors burn out on these boards, there is a fix for this too, the picture is at the bottom of this page). You need to diagnose by removing the lower right plastic kick panel on the passenger side. There you will find a blue plug. With the car OFF stick a paper clip, wire or stuff the plug with foil to make electrical connection so that the two terminals are touching. Then, turn the ignition to ON (not enough to start it though, just power it up). When you do this, count the blinks in the "D Light" or count your blinking Check Engine Light. Both are different but can refer to different things wrong with your car. A long blink is the first number and the short blinks that follow are the second number.
So imagine this as being 14 : ___ _ _ _ _

Below is a decoding chart:

The first section will be the check engine light codes, the next one is the Transmission Control Unit Codes read from the D Light;

1 O2A - Oxygen sensor #1
2 O2B - Oxygen sensor #2
3 MAP - manifold absolute pressure sensor
4 CKP - crank position sensor
5 MAP - manifold absolute pressure sensor
6 ECT - water temperature sensor
7 TPS - throttle position sensor
8 TDC - top dead centre sensor
9 CYP - cylinder sensor
10 IAT - intake air temperature sensor
12 EGR - exhaust gas recirculation lift valve
13 BARO - atmospheric pressure sensor
14 IAC (EACV) - idle air control valve
15 Ignition output signal
16 Fuel injectors
17 VSS - speed sensor
19 Automatic transmission lockup control valve
20 Electrical load detector
21 VTEC spool solenoid valve
22 VTEC pressure valve
23 Knock sensor
30 Automatic transmission A signal
31 Automatic transmission B signal
36 traction control found on JDM ecu's
41 Primary oxygen sensor heater
43 Fuel supply system
45 Fuel system too rich or lean
48 LAF - lean air fuel sensor
54 CKF - crank fluctuation sensor
58 TDC sensor #2
61 Primary oxygen sensor
63 Secondary oxygen sensor
65 Secondary oxygen sensor heater
71 random misfire cylinder 1
72 random misfire cylinder 2
73 random misfire cylinder 3
74 random misfire cylinder 4
80 Exhaust Gas Recirculation insufficient flow detected
86 ECT Sensor (Engine Coolant Temperature) circuit range / performance problem
90 Evaporative Emission Control System leak detected in the fuel tank area
91 Fuel Tank Pressure Sensor low input
92 Evaporative Emission Control System insufficient purge flow

TCU Codes:

CODE LIST:

1-Lock-up solenoid 'A' circuit open or shorted.
2-Lock-up solenoid 'B' circuit open or shorted.
3-Throttle Position Sensor circuit open or shorted.
4-Vehicle Speed Sensor open or shorted - No signal from speedometer.
5-Shift Lever Position Switch circuit shorted.
6-Shift Lever Position Switch circuit open.
7-Shift Solenoid 'A' circuit open or shorted.
8-Shift Solenoid 'B' circuit open or shorted.
9-Counter shaft or transmission speed pulse generator open or shorted.
10-Coolant Temperature Sensor open or shorted.
11-Engine RPM (Ignition coil signal) open or shorted.
12-(No code 12 used)
13-Main shaft speed pulse generator open or shorted.
14-Linear (line pressure control) solenoid open or shorted.
15-Kick down switch circuit shorted.

Hi:
You need to find out what is causing the check engine light before you go any further. Your truck is OBD1, so you can't hook up a newer scanner, but you can jumper a couple plugs and the truck will flash the check engine light to tell you what the code is. BUt easier is to have one of your local auto parts stores check it for you for free. Most will do that for you. You probably have a bad sensor of some sort. It seems that some fail more often than others, such as the coolant temp sensor. These directly effect your engine timing and can cause poor fuel mileage, but have the code scanned and you should have a better idea where to look!

This code refers to the front oxygen sensor on Bank 1. The heated circuit in the oxygen sensor decreases time needed to enter closed loop. As the O2 heater reaches operating temperature, the oxygen sensor responds by switching according to oxygen content of the exhaust surrounding it. The ECM tracks how long it takes for the oxygen sensor to begin switching. It the ECM determines (based on coolant temp) that too much time elapsed before the oxygen sensor began operating properly, it will set P0135.
Repair short or open or high resistance in wiring harness or harness connectors.
Since you have already changed out your O2 sensor (as long as you used to OEM replacement and not the "Universal" replacement) you should not have to replace it again. You might check your thermostat to part of the time it takes for the O2 sensor to start switching being based on coolant temp, if your thermostat is not operating properly, it could cause the coolant temp to take longer than what is considered by the ECM to be normal.