I changed the gasket on the intake manifold upper and lower. On a 98 chevy blazer. And now i have error code 306. It !st was error code 300. The motor is a 4.3 V6

This is a vacuum leak causing the oxygen sensors to throw codes or its both sensors or you have an exhaust leak before the sensorsyou say you changed the intake manifold gasket did you change upper plenum and the lower intake or just the top? Ok let's try this take fuel injection cleaner and spray around the intake upper and lower while in drive foot on the brake if the idle changes the leak is there do the same for all vacuum lines

REMOVE UPER INTAKE 97 EXPLORER V6 4.0 - YouTube

? 12:22
https://www.youtube.com/watch?v=ugExJ0wkP8A
Jun 11, 2013 - Uploaded by Sum Guy
REMOVE UPER INTAKE 97 EXPLORER V6 4.0 ... I was told that all I have to do is remove the fan belt to get access to it ... FordExplorer 2000 intake manifold gasket upper lower P0174 by froggy - Duration: 36:54. by froggy 36,588 views ... Ford Explorer 4.0L SOHC Rough Idle P0171 P0174 Lean Codes ...

Putting the lower intake on my 1997 Ford Explorer 4.0 OHV ...

? 5:23
https://www.youtube.com/watch?v=qKE1vPxqPHs
Jun 27, 2010 - Uploaded by origionaldz
Putting the lower intake on my 1997 Ford Explorer 4.0 OHV sport .... I do have a 2000 5.0 ... @michaelheiland123654 To dothis job, you have to remove the alternator, unbolt the AC compressor, remove upper intake manifold, remove fuel rail,remove all injectors, ... Do you have the SOHC or OHV version?

1999 Ford Explorer 4.0L -need assistance on removing upper intake ...

www.automotiveforums.com > ... > Ford > Explorer ' Explorer Sport Trac

Sep 20, 2011 - 1999 Ford Explorer 4.0L -need assistance on removing upper intake ...Are you sure you have the OHV/pushrod engine and not the SOHC engine? ... Do youhave the upper intake manifold loose, you just are unable to ... the lower intake gasket, valve cover gaskets, Injector o-rings, plugs and wires. Thanks ...

How to replace upper intake manifold gaskets - Ford Explorer

You have to reove the upper plenum. that is the part on top of the intake that looks like a dome on top of the lower intake.There is 8 10mm bolts around the outside of the dome part. the disconnect the fuel lines at back of lower intake and remove the cpi unit.

lower intake manifold

step 1 27 inch lbs.

step 2 106 inch lbs.

step 3 134 inch lbs.




upper intake manifold

step 1 44 inch lbs.

step 2 80 inch lbs.

The upper part of the intake manifold is the plastic part of the assembly, it's held on with small 10 millimeter headed bolts. NOTE: This dosen't have to be removed to replace the lower intake gaskets.

Codes p1537 and p 1538 are codes for a faulty IMRC valve. They are located on the lower intake manifold.

Intake Manifold Runner Control (IMRC), Vacuum Control

1. Remove E-clip retaining vacuum control linkage to lever/shaft assembly.
   

1. Remove adjustment screw from the vacuum control (9S514) and bracket.
   

1. Remove two bolts retaining vacuum control and bracket to IMRC housing assembly.
   

1. Disconnect linkage from the lever/shaft assembly and remove vacuum control .
   

1. To install vacuum control and bracket assembly, reverse Removal procedure. Tighten retaining bolts to 8-11 Nm (71-97 lb-in). Adjust vacuum control as described.
   
   
   Intake Manifold Runner Control (IMRC)
   
   
   
   

As for the misfire codes, Check out the upper and lower intake gaskets. Since you have to take the upper intake off for the imrc valves its just a few more bolts to remove the lower intake. The intake gaskets are rubber seals. When the engine is cold the seals shrink and causes a misfire. when the engine warms up the seals expand and the misfire goes away.

Ihave a 96 s10 lt blazer First of all the steering coloum is now where near the engine block and the bracket you mention is for the throttle cable and the cruise control cable and has no gasket for any kind of a seal with the intake manifold. The 4.3 and most chevy engines have a problem with the intake manifold gaskets if you are over heating then likely the intake manifold gasket is leaking you should check your engine oil for antifreeze that will look like a fomey white yellowey residue and also check the radiator for engine oil floating on the top under the radiator cap. This is a big problem with chevy you can't let espesecly the 4.3 ever over heat.There is olny 8 bolts that hold the manifold to the block and there all in the four corners nun in the middle Y ou can save the engine if you fix it now but it is the intake manifold gasket that is leaking

3.8L Engine (most common) Upper Intake Manifold To Remove:

1. Drain the cooling system.
2. Remove or disconnect the following:
   • Negative battery cable.
   • Fuel injector sight shield.
   • Air cleaner intake duct.
   • Right spark plug wires from the ignition control module and reposition.
3. Relieve the fuel pressure.
4. Remove or disconnect the following:
   • Fuel rail assembly.
   • Brake booster hose from the vacuum source manifold in the upper intake manifold.
   • Exhaust Gas Recirculation Valve (EGR) wiring harness heat shield nut, bolt and the EGR heat shield.
   • Throttle body support bracket upper bolt.
5. Disconnect the electrical connectors from the following:
   • EVAP purge solenoid
   • Throttle Position (T/P) sensor
   • Idle Air Control (IAC) valve
   • Manifold Absolute Pressure (MAP) sensor
   • Mass Air Flow (MAF) sensor
   • EVAP purge solenoid vacuum line from the throttle body.
   • Accelerator and the cruise control cables with the bracket from the throttle body.
6. Remove or disconnect the following:
   • Upper intake manifold bolts and stud.
   • Clean the upper intake manifold bolt threads.
7. Remove or disconnect the following:
   • Upper intake manifold by lifting the back of the intake and sliding the manifold forward from the throttle body support bracket.
   • Upper-to-lower intake manifold carrier gasket from the upper intake manifold.
8. If the upper intake manifold is being replaced, remove the following:
   • Throttle body assembly.
   • Manifold Absolute Pressure (MAP) sensor.
   • Positive Crankcase Ventilation (PCV) valve.
   • Vacuum source manifold.

Upper intake manifold bolt torque sequence (3.8L engine)

To Install:

1. If the manifold was replaced, install or connect the following:
   • Vacuum source manifold.
   • Positive Crankcase Ventilation (PCV) valve.
   • Manifold Absolute Pressure (MAP) sensor.
   • Throttle body assembly.
   • Upper-to-lower intake manifold carrier gasket to the upper intake manifold.
2. Carefully place the upper intake manifold onto the lower intake manifold. Ensure that the alignment pins in the upper intake manifold align with the holes in the lower intake manifold. NOTE: Apply thread lock compound, to the bolt threads before assembly.
   
3. Install or connect the following:
   • Upper intake manifold. Tighten the upper intake manifold bolts in sequence to 89 in lbs (10 Nm)
   • Accelerator and the cruise control cables with the bracket to the throttle body.
   • EVAP purge solenoid vacuum line to the throttle body.
4. Connect the electrical connectors to the following:
   • Mass Air Flow (MAF) sensor
   • Manifold Absolute Pressure (MAP) sensor
   • Idle Air Control (IAC) valve
   • Throttle Position (T/P) sensor
   • EVAP purge solenoid
5. Install or connect the following:
   • Throttle body upper support bracket bolt. Tighten the bolt to 89 in lbs (10 Nm)
   • EGR valve wiring harness heat shield, nut and the bolt. Tighten the nut and the bolt to 89 in lbs (10 Nm)
   • Brake booster hose to the vacuum source manifold.
   • Fuel rail assembly.
   • Right spark plug wires.
   • Air cleaner intake duct.
   • Fuel injector sight shield.
6. Connect the negative battery cable.
7. Fill the cooling system.
8. Inspect for fluid or vacuum leaks.

Lower Intake Manifold (W/O Supercharger) To Remove:

1. Remove or disconnect the following:
   • Upper intake manifold.
   • Generator brace.
   • Drive belt tensioner with the mounting bracket and the heater water bypass inlet pipe.
   • Exhaust gas recirculation EGR outlet pipe bolt from the lower intake manifold.
   • Radiator inlet hose from the water outlet housing.
   • ECT sensor electrical connector.
   • Right upper engine mount strut bracket.
   • Generator brace bracket bolts.
   • Generator brace bracket.
   • Lower intake manifold bolts.
   • Lower intake manifold.
   • Lower intake manifold seals.
   • Lower intake manifold gaskets.
2. If replacing the lower intake manifold, Remove or disconnect:
   • Water outlet housing bolt and stud
   • Water outlet housing
   • Gasket and the thermostat.
   • ECT sensor.
3. Inspect the flatness of inlet flanges.
4. Clean the intake manifold mating surfaces.
5. Clean the intake manifold bolts and bolt holes of adhesive compound.

To Install:

1. If removed, install the ECT sensor.
   • Tighten the ECT sensor to 18 ft. lbs. (25 Nm)
2. If removed, install the thermostat, the gasket, and the water outlet housing.
3. If removed, install the water outlet housing bolt and the stud.
   • Tighten the bolt and stud to 20 ft. lbs. (27 Nm)
4. Install or connect the following:
   • Lower intake manifold gaskets. NOTE: Apply sealer GM P/N 12346286 (Canadian P/N 10953472) or equivalent to the ends of the intake manifold seals.
     
   • Lower intake manifold seals.
   • Lower intake manifold.
   • Lower intake manifold bolts.
   NOTE: Apply thread lock compound GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the two hidden bolts and ensure they are installed.
   
5. Tighten the lower intake manifold bolts in sequence to 11 ft. lbs. (15 Nm)
   
   
6. Install or connect the following:
   • Generator brace bracket.
   • Generator brace bracket bolts. Tighten the bolts to 37 ft. lbs. (50 Nm)
   • Right upper engine mount strut bracket.
   • ECT sensor electrical connector.
   • Radiator inlet hose to the water outlet housing.
   • EGR outlet pipe to the lower intake manifold.
   • EGR outlet pipe bolt to the lower intake manifold. Tighten the bolt to 21 ft. lbs. (29 Nm)
   • Drive belt tensioner.
   • Generator brace.
   • Upper intake manifold.
7. Inspect for leaks.

Lower Intake Manifold (W/ Supercharger) To Remove:

1. Disconnect the negative battery cable.
2. Drain the cooling system.
3. Remove the supercharger.
4. Remove the thermostat housing.
5. Remove the EGR pipe at the intake manifold.
6. Disconnect the electrical connection at the temperature sensor.
7. Remove the intake manifold and gaskets.

NOTE: The coolant bypass tube will release from the intake manifold when the manifold is removed.
To Install:

1. Clean the gasket sealing surfaces.
2. Install the intake manifold gaskets.
3. Align the coolant bypass tube with the opening in the intake manifold and install the manifold. Tighten the bolts to 11 lb ft (15 Nm).
4. Install the electrical connector to the temperature sensor.
5. Install the EGR pipe to the intake manifold.
6. Install the thermostat housing.
7. Install the supercharger.
8. Fill the cooling system.
9. Connect the negative battery cable.

3.8L Engine

NOTE The 3.8L (VIN K) non-supercharged engine uses a two-piece intake manifold consisting of an upper air plenum which mounts the throttle body and a lower intake manifold assembly which houses the fuel injectors. The 3.8L (VIN 1) supercharged engine uses a similar lower intake manifold. The supercharger serves as the upper manifold.
Lower Manifold

NOTE Two bolts which fasten the lower intake manifold to the cylinder head are accessible only after the upper intake manifold is removed. These bolts are located in the right front and left rear corners of the lower intake manifold. Remove the upper intake manifold to service the lower intake.
The 3.8L (VIN 1) supercharged engine uses a manifold similar to the 3.8L (VIN K), but the supercharger serves as the upper manifold.

1. Disconnect the negative battery cable.
2. On 3.8L (VIN 1) engines, remove the supercharger assembly. Please see the procedure in this section.
3. Remove the upper intake manifold using the procedure above.
4. Remove the EGR outlet pipe from the intake manifold.
5. Detach the engine coolant temperature sensor wiring harness from the sensor.
6. Remove the lower intake manifold bolts and carefully lift off the manifold.

To install:


Fig. Lower intake manifold bolt torque sequence-3.8L (VIN K) engine

1. Clean all parts well with degreaser, especially the gasket seal surfaces on the upper and lower manifold pieces and between the lower manifold and the cylinder heads..
2. Install new gaskets to the cylinder heads and new seals to the engine block. Carefully lower the manifold into place. Apply thread-locking compound to the bolt threads. Make sure to install the two hidden bolts in the lower intake manifold. Hand start all bolts, then torque evenly to 11 ft. lbs. (15 Nm). Follow the toque sequence, starting in the center, then working outwards in a circle.
3. Install the remaining components in the reverse order of the removal process.

Upper Intake Manifold (Plenum)

1. Disconnect the negative battery cable.
2. On 3.8L (VIN 1) engines, remove the supercharger assembly. Please see the procedure in this section.
3. Tag for identification, then remove the right side spark plug wires.
4. Disconnect the ignition wires from the fuel rail.
5. Remove the fuel rail. Please see Section 5.
6. Remove the cable bracket from the intake manifold.
7. Remove the throttle body.

NOTE Two bolts which fasten the lower intake manifold to the cylinder head are accessible are accessible only after the upper intake manifold is removed. These bolts are located in the right front and left rear corners of the lower intake manifold.

1. Remove the upper intake manifold bolts and carefully lift the upper intake manifold from the engine.

Fig. Upper intake manifold and bolt torque sequence-3.8L (VIN K) engine
To install:

1. Clean all parts well with degreaser, especially the gasket seal surfaces on the upper and lower manifold pieces.
2. Install new gaskets to the cylinder heads and new seals to the engine block. Carefully lower the manifold into place. Make sure to install the two hidden bolts in the lower intake manifold. Hand start all bolts, then torque evenly to 89 inch lbs. (10 Nm). Follow the torque sequence, starting in the center, then working outwards in a circle.
3. Install the remaining components in the reverse order of the removal process.

If you are talking about 3.4L engine there are only two manifold gaskets. But there are Four Intake gaskets two for the upper intake and two for the lower intake.