Check engine light on, 0430 code

Question edited for clarity.
Question moved to model category.

It is the intake manifold tuning valve that is stuck and fortunately not the Inlet valve itself.

https://www.google.com/search?q=2008+Chevy+Uplander+P2070

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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 .

The problem could be several things and the first thing to test/replace would be the oxygen sensors
Dribbling injectors and/or bad spray patterns is another possibility.
Intake air leaks; gasket or vacuum hose. Blocked crankcase breather.
These engines are particularly sensitive to any poor intake valve seatings. The smallest leakage can cause a lumpy idle and a standard compression check is useless. The key to accurately testing these is a cylinder leakage test.

What year is it ?
DTC P2078: Intake Manifold Tuning (IMT) Valve Position Sensor Circuit High Voltage
Associated with this code or any coded is a diagnostic flow chart ,for testing of the electrical circuit's for the position sensor . If you don't know that ,an know how to test electrical circuit's ,your best bet , take it to a qualified repair . Rather then guessing an just replacing parts .

Circuit/System Description
An intake manifold tuning (IMT) valve is used to change the intake manifold plenum configuration. When the IMT valve is open, the intake manifold is configured to one large plenum. When the IMT valve is closed, the intake manifold is configured to 2 smaller plenums. The IMT valve improves engine performance at low and high engine speeds depending on the engine load. The IMT valve assembly consists of the following:
• A tuning valve
• A microprocessor
• An electric motor
• A hall-effect sensor
• An ignition voltage circuit
• A ground circuit
• An IMT valve control circuit
• An IMT valve signal circuit

P2078
The engine control module detects an open in the IMT valve ground or a continuous short to voltage in either the IMT valve signal circuit or the sensor. This diagnostic runs continuous when the conditions for running are met.
Test the electrical circuit's !!!!!!! you would need a wiring diagram

Circuit/System Testing
Ignition OFF, disconnect the IMT valve harness connector at the IMT valve.
Test for less than 1 ohm of resistance between the IMT valve ground circuit terminal B and ground.
? If greater than the specified value, test the ground circuit for an open/high resistance.
Ignition ON, verify that a test lamp illuminates between the IMT valve ignition 1 voltage circuit terminal A and ground.
? If the test lamp does not illuminate, test the IMT valve ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the fuse for the IMT valve ignition 1 voltage circuit is open, test or replace the IMT valve.
Connect a test lamp between the IMT valve control circuit terminal C and the IMT valve ignition 1 voltage circuit terminal A.
Command the IMT valve ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
? If the test lamp is always ON, test the IMT valve control circuit for a short to ground. If the circuit tests normal, replace the engine control module.
? If the test lamp is always OFF, test the IMT valve control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the engine control module.
Ignition ON, test for 4-6 volts between the IMT valve signal circuit terminal D and ground.
? If less than the specified range, test the IMT valve signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the engine control module.
? If greater than the specified range, test the IMT valve signal circuit for a short to voltage. If the circuit tests normal, replace the engine control module.
Install a 3A fused jumper wire between the IMT valve signal circuit terminal D and ground. Verify the scan tool IMT valve Feedback parameter transitions from 0-100 percent.
? If parameter does not change, test the IMT valve signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the engine control module.
If all circuits test normal, test or replace the IMT valve.

You have an "Engine Miss" and even after replacing spark plugs, wires, upper and lower manifold gaskets, and push rods, the Engine Miss still remains. You may want to stop and run a compression test. This test will give you a base line. If one cylinder has low compression, you won't get rid of the miss until that is fixed. Please write back with all the specific information regarding tests, all symptoms (is the engine light on and if so what are the codes?). The more tests that you perform the more you will know and will narrow down your search. All types of things will cause a miss. Take a look at the spark plugs and wires, just because they are new doesn't mean that they are not defective, also check the EGR valve, 02 sensors and exhaust back pressure, clogged filters (fuel&air), defective coil, TPS sensor, PVC valve, or timing. Please let me know if I can help you some more, good luck.

06 CR-V
when you hit the dear, things can break. what's surprising there?
id get a car safety inspection, road worthy ness checks.....really.
google is not your friend here, not for P1 codes. (unless very careful)
and the P1078 code only works on Hondas.
Not only that autozonded scans may show the wrong code.
why? because their scan tool is junk, ! (SSDD)
the FSM covers that 100% read that. for all the tests.

ill pretend the scan tool is not junk and reads Honda's correctly.]

P1 codes are factory codes, and reading ford, or chev or ? on that will
all be lies. P1078 is:
DTC P1078:
Intake Manifold Tuning (IMT) System Malfunction (High rpm) Stuck
Long.

DTC P1078:
Intake Manifold Tuning (IMT) Syst
em Malfunction (High rpm) Stuck
Long
P1078-0570
General Description
The intake manifold tuning (IMT) valve position sensor is mounted on the diaphragm valve shaft to detect a malfunction in the IMT valve.
The engine control module (ECM) / powertrain control module (PCM)
checks both the IMT solenoid valve command and the IMT valve position sensor output.
If the IMT valve position sensor output is Short (short runners) while the IMT solenoid valve is OFF, a malfunction (IMT remains Short / closed ) is detected and a DTC is stored

(what does this mean)
bar stool answer.
the deer hit my car.
the vacuum line fell of the IMT VSV and now the slave sensor fails.
there are 3 parts to the VSV (PCM command) sends vacuum
to the slave , then slave rod moves, the sensor in the slave
(readback pot) shows that it did move correctly
yours is stuck long.

You most likely have a vacuum leak. This is a common problem. The easiest leak areas are break booster, PCV hose and IMT seals. The more complex are the upper and lower intake manifold seals. These are still fairly simple to replace. I replaced my upper seals and still had a problem so I replaced lower seals and that corrected it. I forgot to reinstall the fuel rail sensor so I had to take it apart a third time. I can now do it in under 20 min. You might want to change your plugs while you have the intake manifold off.

My Jag had the same problem. It was the upper and lower intake manifold seals. Buy the aftermarket FelPros and save big money. Change them yourself and save even more. It's not that hard.

Hello,
Very common concern with the Explorer, Explorer Sport Trac and Ranger with the 4.0l SOHC engine! The upper and lower intake manifold gaskets fail, causing vacuum leaks..It can be Extremely difficult to detect these leaks, because they only leak intermittently (usually in the AM after a cold soak)... As the engine warms up they seal back up! Sometimes the vehicle will idle rough, surge or stall after initial start up, then the symptoms will clear after it gets to operating temperature... Usually there will be no driveability symptoms at all, except the engine light coming on and setting lean codes.. The gaskets have been redesigned to correct this concern..


Bill Andrade Ford Master Technician/ASE Master Technician

change the pcv valve its under the intake manifold