Toyota Repair: Rav4 2004 2.0 petrol misfire and flickering oil light, 2004 rav 4, engine management system

Question
Hello-couple of days back my oil warning light started to flicker? That same evening  when the engine was cold the car was badly misfiring? All strange as  usually very reliable. Anyhow had two engine management system tests done and no fault, but oil light still flickers and will misfire when engine cold but tends to run fine when warmed up. What could this be?  I have a 2004 rav 4 xt4 2l petrol with 87,000 miles on clock.

Answer
The oil you are using may be rated at too high a viscosity, in colder weather use a 5W-20 oil and be sure to use a good filter that doesn't allow oil to drain back. These engines also have some issues with ignition coil packs, there is one per cylinder, the computer should pick up any misfire and store a trouble code so I don't know why there are no codes. If the spark plugs have never been changed then I would try that, they are due to be replaced at 90,000 miles.