318- 125k mileage
about every 100 miles i need to add a quart of oil. i do not see a leak any where. how should i fix the problem?

 

welcome to df.
PLENUM gasket.
do a search or scroll through for about a gazillion posts.

 

Well your truck is burning oil at an extremely large rate!!! Your rings are probably shot, or your valve seals are worn to death.

 

Is it smoking?

 

so check my compression ( what should that be about?)
and replace the seals with plenum

 

150 PSI is normal.

 

once its warmed up no smoke

 

I'm not sure if you just made a typo or not, but you don't replace the seals with plenum, you replace the plenum gasket. The plenum gasket is located on the bottom of the intake manifold. In order to replace it, you must pull the intake manifold off the truck.

A blown plenum gasket will cause loss of power, spark knock (pinging/a rattling noise in the engine under acceleration), and oil burning. If you notice a nice cloud of blue smoke when you start the truck up, it's a good indicator that your plenum gasket it blown.

A quick way to check to see if the plenum is blown is to look down into the throttle body and if you see pooling oil inside the intake, the plenum is blown. The only way to know for sure whether or not it's blown is to do a vacuum test.

 

if you look through the butterflies then you will probably see a film of oil and not a pool. i didn't see the puddle of oil until i took the throttle body off but i did see a coat of oil all over the inside of the intake through the butterflies.

 

did have a vacuum leak not to long ago replaced the house and seemed to be better,
how do u do a vacuum test?