It is possible that it is related to timing, however, because you are having an oil pressure issue, chances are it is related to the oil control valve for variable valve timing. The control valve controls timing based on oil pressure.
What needs done is the control valve / VVT actuator needs checked. Here are general directions for testing. However, it does require a scanner to actuate the components.
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2011 Lexus Truck GX 460 V8-4.6L (1UR-FE)
On-Vehicle Inspection
Vehicle Powertrain Management Computers and Control Systems Variable Valve Timing Actuator Testing and Inspection Component Tests and General Diagnostics Camshaft Oil Control Valve On-Vehicle Inspection
ON-VEHICLE INSPECTION
1UR-FE ENGINE CONTROL: CAMSHAFT OIL CONTROL VALVE: ON-VEHICLE INSPECTION
1. INSPECT CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY
(a)Connect the Techstream to the DLC3.
(b)Start the engine and turn the Techstream on.
(c)Warm up the engine.
(d)Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the VVT Linear (Bank 1), Control the VVT Linear (Bank 2), Control the VVT System (Bank 1), Control the VVT System (Bank 2), Control the VVT Exhaust Linear (Bank 1) or Control the VVT Exhaust Linear (Bank 2).
(e)Check the engine speed while operating the Oil Control Valve (OCV) using the Techstream.
OK:
See Pic 1
If the result is not as specified, check the oil control valve, wiring and camshaft timing gear.
HINT
* Control the VVT Linear (Bank 1): Command to activate the exhaust and intake side oil control valves of bank 1 (Control range: Between -128 and 127%).
* Control the VVT Linear (Bank 2): Command to activate the exhaust and intake side oil control valves of bank 2 (Control range: Between -128 and 127%).
* Control VVT System (Bank 1): Command to activate the oil control valve of bank 1 (Control range: ON/OFF).
* Control VVT System (Bank 2): Command to activate the oil control valve of bank 2 (Control range: ON/OFF).
* Control the VVT Exhaust Linear (Bank 1): Command to activate the exhaust side oil control valve of bank 1 (Control range: Between -128 and 127%).
* Control the VVT Exhaust Linear (Bank 2): Command to activate the exhaust side oil control valve of bank 2 (Control range: Between -128 and 127%)
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If you are not familiar with the technical jargon above, chances are it looks like a foreign language. Please let me know if you have questions. However, based on your description, it sounds like it is oil pressure related.
Let me know.
Joe
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Monday, January 27th, 2020 AT 6:37 PM