I have a 91 Firebird 3.1 V-6 120,000. miles. Runs smooth and does not burn oil at all. Just passed emmisions. I have owned for a month put on 1,600 miles.

Oil pressure has always been over 40 and at idle about 32. So I am out driving I am at a light. I look down and my oil pressure is at about6psi rpm is a 800. I push on the pedal and pressure comes back up to about 40. I get to a station check oil level its good. I start the engine again and everything is fine. Later in the day it does the same thing but now the oil guage does not go over 35 and it idles at 20 and some times just drops to almost nothing at idle. Is it the oil sending unit or do I have big problems.

I also have a noise under the hood that sounds like an old Ford power stearing pump grawl but a little deeper in sound I think it is the air pump but not sure could this be conneted to the oil problem somehow

 

well do you here a loose knocking sound? if so its your bearings or lifters. then yes you do indeed have low pressure. If not.. bad unit. Do you know what noisey lifters sound like. If you hear that its the death noise. no oil.

 

thanks for the input engine sounds fine no knock or top end noise.

 

Well my pressure is always high as all hell... and i only got 60k... most of the time its jus about layin down... i havent a slightest clue y

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White 91 3.1 RS.
T-Tops
12" Sony XS-l1235 Bass tube powered by MTX 2120 amp. Kenwood 8015 Head unit

16" ROH Rims
Firestone Firehawks
ES Urethane Tranny Mount
KYB GR-2 Shocks upfront
K&N Air Filter

 

Have you changed the oil in it yet? If you havn't, then you should. It sounds like the oil is breaking down, and in a high milage engine, it'll give odd gauge readings. I had an '83 3.8 Cutlass that would completly loose oil pressure at idle with about 2500 miles on the oil. Changing it brought it right back up. Gotta love the V-6 oiling systems!

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Ya can't have too many fast Chevys!

 

well older engiens also have problems especially if they weren't properlly maintained in their hay-day. One of these could be a lack of oil changes, which can cause dirt and grime to be moved around inside the oil, and will wear on your oil passages and bearings. This of course is a very bad thing to have happen, and new bearings would end up being needed. If the space around the bearings is to great than the oil pressure will read way low, that's a typical problem with older engines. Hopefully that's not what it is. good luck.

 

I think that's the deal with my engine (+223,000 miles)- When the engine's warmed up, my oil pressure's almost to zero at idle, but goes up to around 40 or 50 when I'm driving around.


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

This car has been babed. Oil changed every 3000 to 4000. Never raced Interior looks brand new. It just lost pressure all at once. Started car today all is fine untll it gets warmed up and then sometimes at idle I lose pressure

 

i ran into pretty much the same exact issue on my car. you want to swap the oil sending unit. its located on the driver's side between the header and firewall (if i remember correctly). very easy...

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'86WS7
Ram Air...
*EiyseWhite*

 

Get a new sensor i put one in 2 weeks ago that fixed my problem same thing u are haveing. When you put your Key in and have the accessories on with out the engine running does the oil pressure guage go all the way down to the right?
YOu can get a new sensor from
WWW.GMPARTSDIRECT.COM i paied 26 bucks for mine that incleded shipping and it was AC Delco.