Changed oil, now very high oil pressure

[MacGeek]

Before I changed the oil the pressure on the gauge, measured in lbs/sq in with a range of 0-45, was between 0 at idle and 45 under acceleration.  I am positive on the low number, might be a bit off on the high number.

Now the pressure is low 30s (~31/32) after first starting.  After it warms up the pressure drops to ~27.  Under acceleration, pegs at 45.  While at constant speed on flat road, about 35.  I don't recall exactly but I think it was low to mid 20s with the old oil.

My 30 year old manual says the pressure might drop to about 7 at idle but that it must go up when accelerating.  Should I be concerned about these new values?  I put in 10w-40, which the manual suggested.

The old oil was awful, I suspect it has been a while since it was changed.  The previous owner lives minutes from work and only put about 5K miles in 3 years on the car.

Do I need to fix something and/or change the oil again with a new weight?  Any suggestions?

[Bandolero]

The only time the oil pressure will be below maximum is when the revs drop below about 1000 - 1500 RPM.
When doing over this, the pressure will go to maximum. (To the stop).

[Big_Richard]

did this oil change include a new filter ? If not, change it immediatley and get someone to slap you in the face

Regarding the pressures, id be more concerned as to why there wasnt any pressure at idle prior to the oil change, hope the engine is ok...

[MacGeek]

did this oil change include a new filter ? If not, change it immediatley and get someone to slap you in the face

I'd be slapping myself first.  I always change the filter when I do an oil change.     Yesterday I found a local parts store that sells AMSoil, so next change I'll probably switch it over to that. 

Regarding the pressures, id be more concerned as to why there wasnt any pressure at idle prior to the oil change, hope the engine is ok...

Me too.  I'm going to have the timing chain checked along with some other stuff as well.