Reccieved P0141, P0147, P0340 as emission diagnostic trouble codes. What do these mean?

No code tells you to replace a part , need to do diagnostic's for said code .
P0141 - O2 Heater Circuit (Bank 1, Sensor 2) Description: See the description for DTC P0135. Possible Causes: See the possible causes for DTC P0135. Diagnostic Aids: See the diagnostic aids for DTC P0135. Application Key On Engine Off Key On Engine Running Continuous Memory All GO to Pinpoint Test DW .
DW: Heated Oxygen Sensor (HO2S) DW: Introduction DW1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS) Are DTCs P0040, P0041, P0053, P0054, P0055, P0059, P0060, P0132, P0133, P0135, P0138, P0139, P0141, P0144, P0147, P0152, P0153, P0155, P0158, P0159, P0161, or P1127 present?
Yes No For DTCs P0040 or P0041, GO to DW2 .

For DTCs P0053, P0054, P0055, P0059 or P0060, GO to DW14 .

For DTCs P0132, P0138, P0144, P0152 or P0158, GO to DW20 .

For DTCs P0133 or P0153, GO to DW3 .

For DTCs P0135, P0139, P0141, P0147, P0155, P0159 or P0161, GO to DW9 .

For DTC P1127, GO to DW19 . For all others, GO to Section 4, Diagnostic Trouble Code (DTC) Charts and Descriptions .
DW9 DTCS P0135, P0139, P0141, P0147, P0155, P0159 OR P0161: CHECK FOR A SOURCE OF POTENTIAL HO2S CONTAMINATION

• Investigate the following items as potential sources of HO2S contamination:
  • use of unapproved silicon sealers
  • fuel contaminated by silicon additives
  • excessive oil consumption
  • glycol leaking internally in the engine
  • lead-contaminated fuel
  • short drive cycles in cold weather
  • use of unapproved cleaning agents

Is a concern present?
Yes No REPAIR the source of the contamination.

CHANGE the engine oil and oil filter.

RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM) .

REPEAT the self-test. GO to DW10 .

P0450 Evaporative Emission Control System Pressure Sensor ...

www.obd-codes.com > p0450

P0450 Evap Emission System Pressure Sensor Malfunction ... This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to ...

P0450 OBD-II Trouble Code: Evaporative Emission Control ...

www.yourmechanic.com > Articles

P0450 is a diagnostic trouble code (DTC) for "Evaporative Emission Control System Pressure Sensor Malfunction". This can happen for multiple reasons and a ...

P0450 - Evaporative emission (EVAP) pressure sensor ...

www.troublecodes.net > pcodes > p0450

Nov 18, 2015 - The code P0450 is set when the ECM reads a voltage signal lower than ... DTC P0453 Evaporative Emission Control System Pressure Sensor ...

13C-DTC P0450: Evaporative Emission Control System ...

mitsubishitechinfo.com > data > HTML

DTC P0450: Evaporative Emission Control System Pressure Sensor Malfunction. CIRCUIT OPERATION. The ECM (terminal No. 114) supplies a 5 volts ...

clouds of smoke out the rear exhaus ,What color ? blue smoke is oil , white smoke is most of the time coolant is getting into the engines cylinders , Black the engine is running rich ,too much fuel . DTC P0135 HO2S Heater Performance Bank 1 Sensor 1
DTC P0147 HO2S Heater Performance Bank 1 Sensor 3
DTC P0340 IC Module Cam Reference CKT No Frequency
DTC P0401 Exhaust Gas Recirculation (EGR) Flow Insufficient
P0441 has nothing to do with the gas cap !
DTC P0441 Evaporative Emission (EVAP) System No Flow During Purge
DTC P1441 Evaporative Emission (EVAP) System Flow During Non-Purge

P0441 & P1441 will be back , may take a day or two , but will be back because gas cap has nothing to do with it .

Honestly , you should take your vehicle to a qualified repair shop !

it sounds like a faulty oxygen/o2 sensor

• P0340 - Camshaft position sensor circuit malfunction.
  
• P0457 - Evaporative emission control system leak detected (fuel filler cap loose/off)
  
  There is a bulletin #0398 posted on 05/12/2003 for P0457 - Malfunction indicator lamp (mil) illumination with diagnostic trouble codes p0442, p0455, p0456, p0457, p1442 or check fuel cap lamp illuminated with diagnostic trouble code p0457.

I'd suggest checking with your local dealer, as it may be a fix that is covered by the dealer.

P0442 FORD - Evaporative Emission System Leak Detected Small Leak

Possible causes- Missing or loose fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking
P0136 - O2 Sensor Circuit Malfunction Bank 1 Sensor 2
Possible causes- Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
- Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
- Faulty Rear Heated Oxygen Sensor Bank 1
- Inappropriate fuel pressure
- Faulty fuel injectors
- Intake air leaks may be faulty
- Exhaust gas leaks

P0141 FORD - O2 Heater Circuit Bank 1 Sensor 2

Possible causes- Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2
- Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit fuse
- Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit open shorted to ground
- Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit poor electrical connection
- Faulty Engine Control Module (ECM)

diagnostic trouble code table,it can tell you the meanning of the p0340,

Here is what each of your trouble codes means:

DTC P0108 MAP Sensor Range check High
DTC P0121 TPS Circuit Range/Performance Problem
DTC P0340 Camshaft Position Sensor Circuit Malfunction
Do you know how long each of these codes have been stored? Each one of these codes relate to a different part of the vehicle.

Your PO108 codes is probably a faulty Manifold Absolute Pressure Sensor
PO121 is a Throttle Position Sensor malfunction code
PO340 is a Camshaft Position Sensor malfunction code

I would not think that all 3 of these codes all set at the same time, just wouldnt make sense unless there was a problem with the Engine Control Module (ECM) causing all these codes to set at the same time.

P0135 means 0xygen heater circuit malfunction, P0141 mean 02 heater circuit bank1 sensor 2 (this is catalytic monitor) P0147 means 02 heater sensor circuit bank 1 sensor 3, P0300 is random misfire. You will get all the 02 code because of the misfire correct the misfire and the 02 should correct.We will start with the plug wire and make sure the firing order is correct 1996 chevy blazer that will make it a 4.3 engine size check the firing order firing order is 165432 also check the coil (it has a tendency to short you will know if it is) make sure the distributor rotation is check

p0136 and p0141 are o2 sensors and p0401 is a egr flow and the p0171 means its running lean on low bank 1