my truck has been getting gradually worse in smoking and using oil. i did a compression check today and got 120 150 155 155. as far as oil pressure when driving down the road(2-2500rpm) the gauge shows around 55psi and while hot and idling about 15-20. it smokes the worse when cranking it up and first start driving, but will also smoke some when reving it up. it sounds like the heads are in need of some work to me, not sure about the rest of the engine?the truck had 175,000 miles when i bought it now it has around 225,000 miles, i dont know any history of the engine exept at about 200,000 i put a head gasket and timing set in it.

Check the valve adjustment on the cylinder with the low reading, make sure neither valve is tight.
I really don't know a lot about the napZ engine other than they blow head gaskets unless the head bolts are re-torqued every tune up.

wlf89 wrote:my truck has been getting gradually worse in smoking and using oil. i did a compression check today and got 120 150 155 155. as far as oil pressure when driving down the road(2-2500rpm) the gauge shows around 55psi and while hot and idling about 15-20. it smokes the worse when cranking it up and first start driving, but will also smoke some when reving it up. it sounds like the heads are in need of some work to me, not sure about the rest of the engine?the truck had 175,000 miles when i bought it now it has around 225,000 miles, i dont know any history of the engine exept at about 200,000 i put a head gasket and timing set in it.