98z28jorge

iTrader: (4)

i have a 98 z28 that has 115k miles the car runs fine with no problems its just that i thought the oil pressure should be around 40 but after driveing for a while i get to a stoplite and the pressure drops to 20-15 and some times shakes what can the problem be i was told to use 20w50 oil and that sould fix the problem is this true???

Cape T/A

i would not run that heavy of an oil on a stock pump, its not a 1970 smallblock.

TURBO6.0L

iTrader: (1)

Verify your oil pressure with a mechanical gauge if you are not already doing that. Not sure what oil pressure would have to do with a shake. Does it feel like you are going to stall when it shakes? What weight oil you running now. My old LS1 did not like valvoline 5w30. It would run around 30 at idle. Put any other brand of oil in it and it was around 40.

Cape T/A

is something causing it to ilde real low, if so that would explain the shake and oil pressure.

98z28jorge

iTrader: (4)

the car idles at about 800 rpm dont know if its low and i use to run royol purple 5w30 and i switched to mobile one 10w30 and no change

1BAD_LS1

iTrader: (36)

dont use 20/50 in an ls1!!!!! as for the shake at idle could be alot of things...

does it smoke a little if you gun it?
pull your oil cap at an idle, is there blowby? (smoke blowing out oil cap)
do the rpms fluctuate at all or are they steady?

we need some more info man!

98z28jorge

iTrader: (4)

the rpms are steady when the car is on drive and stopped when its hot the oil pressure drops to about 20 and sometimes the niddle shakes up and down to 20-15 and then just stays still and does it again but only does this while the car is warm if its cold it stays at 40

98z28jorge

iTrader: (4)

so what do you guys think i should do what oil should i run or the sending unit or the pump something i need help here

venom ws7

iTrader: (13)

Change the oil 10w30.

Maybe you cam bearings or oil pump is dying??

01ssreda4

iTrader: (96)

Sounds like an oil pump to me. I had the exact same problem with a 4.3 motor. It was exactly as you described. New pump and the pressure shot up like it was a brand new motor.