brand new motor roughly 500 miles on it when iI started it in the morning or first start of the day my oil pressure rises to 65 to 75 and when you drive it say a about 5 mins of driving and you come to a light oil pressure drop to about 10 to 15 but when you give gas it will raise back up to 50 to 60 what could be the issue ever part is brand new i scanned the car and it reads code number 43 but im pretty sure that has nothing to do with oil pressure any help will due.

 

what oil and what oil filter? fram paper filters will go apart.

 

I'm using 20 50 with fram tough gaguard changed oil twice same problem

 

What issue are you talking about? You described exactly how a new stock motor should act. It is possible for a new motor to have 60 PSI of pressure at idle but its not a requirement or even needed in anyway. Infact 60 PSI at idle is just eating up gas.

 

So your saying a brand new motor at idle would hold a low oil pressure? All I'm ask or saying is I rebuilt a new motor every part new and when I first start the car the oil pressure would hold to about 60 to 70 but when you go drive it about a mile or two and come to a light the oil pressure drops and hold to about 10 to 15 and when you give it gas at the light or accelerate the oil pressure will rise so my concern is y it drops so low at idle?

 

Cold oil is thick therefore generates more pressure and visa versa. The higher the rpms the faster the oil pump shaft is turning causing increase in pressure.

 

I understand that but why is the oil pressure at idle or when u come to a light or not on the throttle y is the oil pressure low

 

A new engine dropping down to 10 psi at idle isn't good in my book. At idle, mine starts out at 80 psi cold, then drops to maybe 30 when it's hot. Apples and oranges to your engine I know, but still it's relative. What kind of an oil pump did you use? That could have some bearing (no pun intended) on things. Mechanical or electric oil pressure gauge? If electric, the oil pressure switch could be faulty.

 

what engine is this? 20w50 is kinda thick to use in a new motor.

 

.... but wouldn't cause low oil pressure at idle, especially when hot.