Would faulty EGR valve cause check engine light to come on?

The PO 316 is still misfires om first 1000 revolutions
so the shop did a poor job for you on resolveing the
cylinder misfires

Try a diffferent shop

Have to clean the MAF Sensor & replace upstream
oxygen sensors if over 100,000 miles

Need the correct oem spark spark plugs/any brand

No reason the gas filter should be clogged unless it was in
the car for 10 years

Fuel pressure should be checked

Need to check for cylinder misfires on a road test of 20
miles or more with professional software in Mode#06

Here is a list of possible causes. Some things you have already done.

EGR solenoid valve harness is open or shorted
- EGR solenoid valve circuit poor electrical connection
- EGR volume control valve stuck closed
- Faulty EGR Pressure sensor
- Faulty EGR temperature sensor and circuit
- Faulty EGR Valve
- EGR passage clogged
- Exhaust gas leaks
Read more: http://engine-codes.com/p0401_ford.html#ixzz28fATCih2

Your only problem here friend is a faulty EGR valve. It WILL make you lose power on a grade and sometimes cause a hesitation at takeoff. This unit is called the Exhaust Gas Recirculation(EGR) valve and is incorporated into the vacuum and exhaust of the engine. It could be just that it's losing vacuum to this valve so check the vacuum line that it is still connected and not cracked.

Technical Description

Knock Sensor Circuit Malfunction
What does that mean?

A knock sensor tells the engine computer when one or more of your engine's cylinders are "knocking", that is, exploding the air/fuel mixture in a way that delivers less power and can be damaging to the engine if prolonged. The computer uses this information to tune the engine so that it doesn't knock. If your knock sensor wasn't operating properly, so that it was always indicating a knock, the engine computer's response may have been to change the ignition timing on your engine. Knock sensors generally bolt into or thread into the engine block. This P0325 code may show up intermittently or the Service Engine light may be lit constantly. Other knock sensor related DTC codes include P0330.
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You may notice drivability problems including a lack of power and perhaps some hesitation. There may also be other symptoms.
Causes

A code P0325 most likely means one or more of the following has happened:

• The knock sensor is faulty and needs to be replaced
• There is a wiring short/fault in the knock sensor circuit

Possible Solutions

• Check the resistance of the knock sensor (compare it to factory specs)
• Check for broken/frayed wires leading to the sensor
• Replace the knock sensor

Sources: W. Farmer - Nissan

P0400 - Exhaust Gas Recirculation Flow Malfunction OBD-II Trouble Code Technical Description

Exhaust Gas Recirculation Flow Malfunction
What does that mean?

The exhaust gas recirculation (EGR) valve is vacuum controlled valve that regulates the amount of exhaust gases that re-enter the cylinders. The powertrain control module (PCM) determines how much based on engine load, temp, and other conditions. If the PCM detects that the amount of exhaust gases entering the cylinder were insufficient or non-existent, this code is set.
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No symptoms will likely be noticed by the driver other than the MIL (malfunction indicator lamp). However, non visible symptoms will be increased combustion temperature and increased Nox emissions.
Causes

A code P0400 may mean that one or more of the following has happened:

• Plugged EGR passage which restricts the flow of exhaust gasses
• Faulty EGR solenoid
• Faulty EGR solenoid wiring/harness
• Vacuum lines damaged/disconnected to the EGR valve solenoid or to the EGR valve
• Faulty EGR valve

Possible Solutions

Since EGR valve designs are different, no one test will suffice:

• Using a scan tool, operate the EGR valve with the engine running. If the engine stumbles, the problem was likely intermittent wiring problem or intermittent blockage problem
• If engine doesn't stumble, operate the EGR valve manually, if possible. If engine doesn't stumble and die, the ports are likely plugged. Removal of valve and cleaning of all ports will be required
• Checking of solenoid can only usually be done with a scan tool, because most solenoids operate with a duty cycle of voltage, rather than constant voltage
• Check all vacuum lines, hoses, etc for any damage
• Visually inspect the solenoid harness and the solenoid for damage
• Replace EGR valve

P0400 - Exhaust Gas Recirculation Flow Malfunction
The exhaust gas recirculation (EGR) valve is vacuum controlled valve that regulates the amount of exhaust gases that re-enter the cylinders. The powertrain control module (PCM) determines how much based on engine load, temp, and other conditions. If the PCM detects that the amount of exhaust gases entering the cylinder were insufficient or non-existent, this code is set.

Symptoms: No symptoms will likely be noticed by the driver other than the MIL (malfunction indicator lamp). However, non visible symptoms will be increased combustion temperature and increased Nox emissions.

Causes: A code P0400 may mean that one or more of the following has happened:
Plugged EGR passage which restricts the flow of exhaust gasses
Faulty EGR solenoid
Faulty EGR solenoid wiring/harness
Vacuum lines damaged/disconnected to the EGR valve solenoid or to the EGR valve
Faulty EGR valve

Possible Solutions: Since EGR valve designs are different, no one test will suffice:
Using a scan tool, operate the EGR valve with the engine running. If the engine stumbles, the problem was likely intermittent wiring problem or intermittent blockage problem
If engine doesn't stumble, operate the EGR valve manually, if possible. If engine doesn't stumble and die, the ports are likely plugged. Removal of valve and cleaning of all ports will be required
Checking of solenoid can only usually be done with a scan tool, because most solenoids operate with a duty cycle of voltage, rather than constant voltage
Check all vacuum lines, hoses, etc for any damage
Visually inspect the solenoid harness and the solenoid for damage
Replace EGR valve

Hope this helps.

P0400 - Exhaust Gas Recirculation Flow Malfunction

The exhaust gas recirculation (EGR) valve is vacuum controlled valve that regulates the amount of exhaust gases that re-enter the cylinders. The powertrain control module (PCM) determines how much based on engine load, temp, and other conditions. If the PCM detects that the amount of exhaust gases entering the cylinder were insufficient or non-existent, this code is set.
Symptoms:
FB.init("dd7d9e9681341cde77587bc6a2029f6f"); OBD-Codes.com on Facebook No symptoms will likely be noticed by the driver other than the MIL (malfunction indicator lamp). However, non visible symptoms will be increased combustion temperature and increased Nox emissions.

Causes: A code P0400 may mean that one or more of the following has happened:

• Plugged EGR passage which restricts the flow of exhaust gasses
• Faulty EGR solenoid
• Faulty EGR solenoid wiring/harness
• Vacuum lines damaged/disconnected to the EGR valve solenoid or to the EGR valve
• Faulty EGR valve

Possible Solutions: Since EGR valve designs are different, no one test will suffice:

• Using a scan tool, operate the EGR valve with the engine running. If the engine stumbles, the problem was likely intermittent wiring problem or intermittent blockage problem
• If engine doesn't stumble, operate the EGR valve manually, if possible. If engine doesn't stumble and die, the ports are likely plugged. Removal of valve and cleaning of all ports will be required
• Checking of solenoid can only usually be done with a scan tool, because most solenoids operate with a duty cycle of voltage, rather than constant voltage
• Check all vacuum lines, hoses, etc for any damage
• Visually inspect the solenoid harness and the solenoid for damage
• Replace EGR valve

Hope helps (remember comment and rated this).

Usually the EGR valve problems show the fault code P0400 - Exhaust Gas Recirculation Flow Malfunction

What does that mean?
The exhaust gas recirculation (EGR) valve is vacuum controlled valve that regulates the amount of exhaust gases that re-enter the cylinders. The powertrain control module (PCM) determines how much based on engine load, temp, and other conditions. If the PCM detects that the amount of exhaust gases entering the cylinder were insufficient or non-existent, this code is set.


Symptoms
No symptoms will likely be noticed by the driver other than the MIL (malfunction indicator lamp). However, non visible symptoms will be increased combustion temperature and increased Nox emissions.


Causes
A code P0400 may mean that one or more of the following has happened:
* Plugged EGR passage which restricts the flow of exhaust gasses
* Faulty EGR solenoid
* Faulty EGR solenoid wiring/harness
* Vacuum lines damaged/disconnected to the EGR valve solenoid or to the EGR valve
* Faulty EGR valve


Possible Solutions
Since EGR valve designs are different, no one test will suffice:
* Using a scan tool, operate the EGR valve with the engine running. If the engine stumbles, the problem was likely intermittent wiring problem or intermittent blockage problem
* If engine doesn't stumble, operate the EGR valve manually, if possible. If engine doesn't stumble and die, the ports are likely plugged. Removal of valve and cleaning of all ports will be required
* Checking of solenoid can only usually be done with a scan tool, because most solenoids operate with a duty cycle of voltage, rather than constant voltage
* Check all vacuum lines, hoses, etc for any damage
* Visually inspect the solenoid harness and the solenoid for damage
* Replace EGR valve


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Hope this helped (remember comment and rated this).

P0401: Isufficient Flow Detected in EGR system.
-clean the EGR port with the carburetor cleaner.
-clean the EGR passage inside the EGR valve with the caburetor cleaner.
Reset the light, if the light still coming back, then replace the EGR valve.

the egr valve could be sticking causing this issue put a vacuum gauge on the egr valve to draw a vacuum then release it to see if it sticks

Your EGR valve appears to be leaking. The valve is most likly dirty or sticking causing the exhaust gasses to enter the intake manifold and causing the missfire. At highway speeds is when the exhaust gas is allowed in the engines intake system for combustion chamber cooling and emissions purposes.
I would suggest removing the EGR, cleaning the valve and have the valve checked.
Good luck.