Missing 3 bolts for my oil pan, will this effect my oil pressure?

No.

The only connection your missing bolts might have is if oil leaks out and you don't have any. Then you won't have any oil pressure.

If the bolts came out, go to the dealership and get some, and snug them tight. If they are broken off, only an expert can get them out without making further problems.

You really should have all the bolts in the oil pan.

No effect, but the consequence could be heavy leaking. After too much oil leaks out, there will be no oil pressure. Replace the bolts so that doesn't happen.

it won,t effect your oil pressure but it might cause a oil leak ! take one of the bolts out and see if you can find 3 bolts at the junk yard !

The oil pan may leak but oil pressure is regulated by the length of the gears in the oil pump and the tension of the oil pump pressure SPRING.

If you've lost a few bolts, don't try to compensate by overtightening the others: you'll just provoke a leak. Replace the lost ones - tighten all uniformly.

Not immediately.

But chances are your sump gasket will start leaking, and if you run low on oil, you will loose oil pressure.

The affect will be no effect on pressure.