HI, on my car in the morning i always get a oil reading of around 20-30 but after car start warming up it drops and bobs from 0-10 but usally its on 0 and bobs when i step on the gas. What do you think is the problem?

 

Try a sending unit first.

If that doesn't change it, the motor probably needs main & rod bearings. Avoid abusing it until you fix it, or you may find yourself walking to work in the morning.

 

A mechanical gauge to verify pressure wouldn't hurt, either.

 

i wish i knew someone who can rebuild my engine.

 

Not to insult you or anything, but did you check your oil level?

 

yea i just chaged it like a week ago. only leaks i got is from my tranny.

 

do these gauges usually go bad, my friends goes to zero sometimes but it does not knock?

 

mine doesnt knock......maby a rattle every now and then but all cars have there noises, no extreme noises

 

So do as stated above. Replace the sender and/or check with a mechanical gauge.

 

i had a 350 that ran for two weeks with zero oil pressure (broken gauge and blown RMS), and it didnt make any noises to tell me something was wrong. mine is proof that gauges do indeed go bad. by the time i figured out where all the oil was going, i had visible metal shavings in the oil.

 

what and where is the sender? and how do i check if my guage is broken?

 

The sending unit is the part that has oil pressure on one side, and the wire to the gauge on the other. It responds to the oil pressure and tells the gauge what to read.

The gauge itself almost NEVER breaks. If it reads wrong, it's ALMOST ALWAYS because the sending unit is broke.

It's either right behind the distributor, or right above the oil filter. I don't fool around with TBI motors, so I don't know which of those 2 possible available places they put it in those. It's a sort of can looking thing about 2" long and an inch and a half in diameter, with a single wire dark blue wire going to a blade connector on it. If you find something like that in either of those 2 places, that's it.

 

It will probably have a 3 wire weatherpack connector on it and be just above the oil filter.

 

Mine used to go to 0 then to 60 then back to 0. I got a crappy Autozone brand one and it stayed at 30 all the time. I got a good GM unit and it worked perfect then.

 

Its right next to the oil filter on my 91 RS. I replaced it a few months back.

Also, when is the last time you had an oil change? If you have old oil it could be part of your issue. Another option is to run straight 30W oil to see if you gain some oil pressure.

 

my gauge has been on zero since i bought my 88 rs a year ago, it doesnt bobble up and down, it just always rests at the bottom, so i take it i've got a broken gauge or sending unit, never bothered to worry about it though

 

 

My car when I first bought it would sit at 30 at startup , then 20-25 warmed up. I used a bottle of Lucas heavy duty oil stabalizer and now I get 30-35 psi all the time. I can verify this because I used a mechanical gauge to check it. But I recently replaced my intake manifold gasket and I was cleaning some sludge out of my lifter valley, I tried to vaccum it all up, but apparently I missed some becasue now my oil pump screen is clogged and I burnt through my bearings and Im in the hole for a new crank , rod and main bearings , and an oil pump. It ran fine with no oil pressure for atleast a month.