Phase 1 Megane Coupe 1.6 oil pressure question.

Sometimes when I'm starting my car the word "oil" starts flashing in the little display (the one that shows the milage) anywhere from 1-5 minutes.

I checked with a garage and they say it's because of low oil pressure, but why would the oil pressure be low sometimes and not all the time?

It does not matter how hot or cold it is outside either.

When I check the oil on the dipstick it's right on the "Max" mark regardless if the engine is warm or cold and the car's not leaking oil either.

This is really bugging me as it's happend twice in almost 3 weeks.

Any help would be great, but I'm not very used to working on cars.

Thanks!

i'd put money on that the filter on the bottom of the oil pick up is blocked so its not picking the oil up properly

to check get the car up in the air and take the sump off and there should be a pipe sticking down with like a wire mesh thing over the end, take the mesh off and clean it then refit, keep an eye on it and if it does it again you may need to get ahold of a new oil pump

Thanks Mario