2012 Sonata still gives code P0087 after replacing both the high pressure fuel regulator and the fuel pump and still takes a while to crank over when cold. If the engine is warm, it cranks fine.

P0087 is Fuel Rail/System Pressure - Too Low, indicating a fuel system problem.

What causes the P0087 code?

• The most common cause is a clogged fuel screen or filter
• A failing fuel pump
• A restricted fuel line
• Improperly reading fuel pressure sensor will set P0087 as well

What are the symptoms of the P087 code?

• Check Engine Light illuminated on the dashboard
• Vehicle may run poorly
• Loss of engine power, noticed during acceleration
• Engine misfire
• Vehicle may stop running

How does a mechanic diagnose the P0087 code?

• A mechanic will begin by using a scan tool to read any codes present.
• Once these codes are identified and the freeze frame information looked at for each code they will be cleared.
• Next a road test will be performed under similar conditions as the freeze frame data.
• If the Check Engine Light comes on a visual inspection of the fuel tank, fuel lines, and fuel filter will be performed.
• Manual fuel pressure readings will then be taken at the fuel rail and compared to specifications. A scan tool will then be used to compare manual readings to what the ECM sees.
• Lastly, the fuel pump will be tested.

Common mistakes when diagnosing the P0087 code

• Mistakes are made when steps are skipped or not completed.
• Though the most common cause is a clogged fuel filter this will not fix all vehicles and circumstances.
• It is important to follow the steps so unnecessary repairs are not performed wasting time and money.

How serious is the P0087 code?

P0087 can lead to serious drivability issues. If the vehicle starts running poorly and having misfires it must be diagnosed ASAP to ensure safe driving. If the fuel pump is failing or the fuel filter becomes completely clogged, this may cause the engine to die while driving resulting in serious issues for the driver. A qualified mechanic should be contacted and repairs should be done to get the vehicle safely back onto the road.

What repairs can fix the P0087 code?

• Replacing the fuel filter or screen
• Replacing kinked fuel lines
• Removing and replacing the fuel pump
• Replacing a faulty fuel pressure sensor

Additional comments for consideration regarding the P0087 code

A manual fuel pressure tester is needed to diagnose P0087. This allows us to check fuel pressure at the fuel rail and then use the scan tool to check what the fuel pressure sensor is reading. Both of these readings are needed to test the fuel pressure sensor.
An advanced scanner is also needed to monitor fuel pressure sensor data.
Some vehicles may not be equipped with an external fuel filter. These vehicles will only be equipped with the fuel screen that is attached to the fuel pump. These are generally replaced as one unit since the gas tank must be removed from the vehicle in most cases.
Care should be taken when test driving a vehicle with a failing fuel pump. If the fuel pump is failing it may do so when driving causing the vehicle to die while driving or not be able to be restarted.

What about the fuel filter

DTC P0087: Fuel Rail Pressure (FRP) Too Low

Circuit/System Description
The fuel injection pump supplies high pressure fuel to the fuel injection rails, and then to the fuel injectors through high pressure pipes. The fuel rail pressure (FRP) sensor is a three wire sensor mounted in the right fuel injection rail. The FRP sensor uses a 5-volt reference circuit , a signal circuit, and a low reference circuit to monitor fuel rail pressure. This information is sent to the engine control module (ECM) to assist in the fueling of the engine.

Fuel Pressure Regulator Solenoid Supply Voltage
P0088, P0090
P0088
P0090
P0087, P0191, P2510
Conditions for Setting the DTC
P0087
• The actual FRP is more than 15 MPa (2,176 psi) below the desired FRP.
OR
• The actual FRP is less than 22.5 MPa (3,263 psi).

Action Taken When the DTC Sets
• DTCs P0087 and P0088 are Type A DTCs.
• The ECM commands the engine to operate in the Reduced Engine Power mode.
• The message center displays Reduced Engine Power.

Important: Because of the cleansing properties of the biodiesel, switching from the straight diesel to a biodiesel blend can prematurely restrict the fuel filter with normal deposits in the fuel system. A fuel filter replacement might be required sooner than the recommended interval.
P0087
If DTC P0090, P0168 or P0191 is also set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
Ignition ON for 90 seconds, verify the scan tool FRP Regulator Command parameter is less than 20 percent.
? If greater than the specified range, replace the ECM.
Attempt to start the engine.
? If the engine does not start, refer to Engine Cranks But Does Not Run.
Install the CH-48027 to the fuel rail service port and slowly increase the engine speed until reaching wide open throttle (WOT). The value should be between 1-4 inches Hg vacuum.
? If more than the specified value, inspect for restricted fuel filter or damaged supply lines.
? If no restriction was found, test for high fuel return flow. Refer to Fuel System Diagnosis - High Pressure Side.
With the engine idling or at an idle, command the fuel pressure control to 180 MPa (26,106 psi) with a scan tool. Observe the Actual Fuel Rail Pressure parameter. The actual fuel pressure should be the same as the commanded pressure.
? If the Actual Fuel Rail Pressure is less than 165 MPa (23,931 psi), refer to Fuel System Diagnosis - High Pressure Side.
Important: If the fuel temperature is near 121°C (250°F) during the duplication of the complaint, or in the Failure Records for this DTC, inspect for a restriction in the fuel cooler air flow or the fuel heater always ON. Refer to Fuel Heater Always On.
Operate the vehicle within the conditions for which the customer complaint occurs while observing the CH-48027 . You may also operate the vehicle within the conditions that you observed in the Freeze Frame/Failure Records.
? If the vacuum was more than 12 inches Hg of vacuum at any time in the operating range, inspect for kinked or restricted fuel supply lines.
Operate the vehicle within the conditions for which the customer complaint occurred. Observe the Actual fuel Rail Pressure and Desired Fuel rail Pressure parameters with a scan tool. Fuel pressures should be the same for both parameters.
? If the Actual Fuel Rail Pressure is less than the Desired Fuel Rail Pressure, refer to Fuel System Diagnosis - High Pressure Side.
? If fuel system tests normal, refer to Diagnostic Aids.

for code p0087 replace the GDI GASOLINE DIRECT INJECTION (HIGH PRESSURE PUMP( the pump is in the top o the engine down the plastic cover- they have two gasoline lines an one electrical connector,and 2 bolts . remove return line, remove the electrical connector, loose the 19mm bolt for the main gasoline line dont move this line, remove bolts of the pump and move it away, when you work with gasoline lines is dangerous (it is at you own risk( THE CODE P0191 IS RELATED FOR FUEL RAIL PRESSURE SENSOR usually appears with p0087. symtoms of bad fuel pump: long cranking time,,erratic idle. not enough power. no start condition= pump is easy to change=

this code is for low pressure so check the fuel filter and pump

(LOW FUEL RAIL PRESSURE)
First: try changing your fuel filter.
If that don't work you may have a faulty fuel pump or a clog along the line. Good luck.

Check high pressure fuel oump output

code p0087 is pressure too low--- causes include fuel supply pipe blockage and code p0088 refers to fuel return line blockage. While you have changed every thing covered in the causes I suggest you have a look for a common point that the pipes run together that could be kinked or squashed . The low fuel pressure could be from a vacuum in the tank from a faulty cap . If the lines are rubber and run in the boot check that something like a spare tyre is not cutting off fuel supply and return

P0204 is miss fire detected on #4 cylinder.

Below is TSB from VW on your problem...a common one.


Technical Product Literature Transaction No.: 2015153/1
MIL ON, DTC P0087, P1093 or P2293 Stored in ECM Fault Memory Release date: Jun 29, 2007
Condition
15 07 04 June 29, 2007 2015153
MIL ON, DTC P0087, P1093 or P2293 Stored in ECM Fault Memory
MIL ON with the following DTCs may be stored in ECM fault memory:
DTC Description
P0087 Fuel Rail / System Pressure - Too Low
P1093 Fuel Trim 2, Bank 1 Malfunction
P2293 Fuel Pressure Regulator 2 Performance

Technical Background
Excessive wear of intake camshaft lobe that drives the high pressure fuel pump. The wear limits maximum pump piston lift, causing fuel rail pressure fluctuations.
The wear on the camshaft lobe can also lead to wear on the base of the high pressure fuel pump cam follower.
Production Solution
Increase surface hardening of camshaft lobe for the high pressure fuel pump
Improved intake camshafts have Part No. 06F109101B.
Service

• Remove the high pressure fuel pump and visually inspect:
1. Base surface of the cam follower -6- in contact with the camshaft lobe.
2. Tip of the high pressure fuel pump plunger.
3. High pressure fuel pump camshaft lobe.

If the base of the cam shaft follower looks like -C- or -D-, no excessive wear is present.
Cam follower and camshaft should not be replaced.
If the cam follower base surface is excessively worn so that its surface is concave -B- or missing -A-, inspect the intake cam shaft lobe for wear.



If the high pressure fuel pump camshaft lobe shows excessive wear, replace the intake camshaft with Part No. 06F109101B and the cam follower with Part No. 06D109309C, see Group 15 Engine - Cylinder head, Valvetrain in ElsaWeb.

Inspect the tip of the high pressure fuel pump plunger for excessive wear.
If excessive wear is found the high pressure pump must also be replaced, see Group 20 Fuel supply in ElsaWeb.
Tip:
High pressure fuel pump plunger damage is only possible if the cam follower base has a hole in it and the plunger tip has come in direct contact with the camshaft lobe.
If no excessive wear can be found in the high pressure fuel pump cam follower or intake camshaft lobe, or if the damage is found in camshafts with part number 06F 109 101 B, create a Technical Assistance Contact Ticket under the Concern Type Engine and Engine Electronics in ElsaWeb.
Attach the complete diagnostic log to the contact, and call the VW Technical Assistance Center for further assistance.

Warranty
When procedure applies to vehicles within the New Vehicle Limited Warranty, use the following:
Claim Type: W2
Part Identifier: 1505
Damage Code: 1505 18 _ _ _* 2
Labor Operation:
2.0T FSI engine Use applicable SRT time in ElsaWeb
Diagnostic Time: Actual GFF time expenditure
Claim Comment: Input "As per Technical Bulletin 2015153" in comment section of Warranty Claim.

* Code per warranty vendor code policy.
Required Parts and Tools
Description Part No: Quantity
Intake Cam Shaft 06F109101B 1
Cam Follower 06D109309C 1

No Special Tools required.

P0087- low pressure fuel system. Fuel pressur valve stock open, Fuel volume control valve stuck close, Leaking fuel injector,P0088- fuel pressure contorl valve stuck close, Fuel rail pressure sensor P2291-all @ at the above, means to say poor fuel quality