| knock and low oil psi
Running a guy @ 125 minutes later heard a knock and pulled home to low oil psi chime on DIC. Pressure fluctuates especially at first. When cold it was anywhere from 30-55psi, warm it was 20 down to 0psi.All with mechanical guage as well.
Changed oil and filter
Changed fuel filter and checked balance rates, 2 were in the -4. range and one in the +7. range.
Dealer turned off cylinders and knock was consistant but they won't look at anything else, they want to sell me a new engine.
Took it to a new mechanic, he believes it's a fuel knock......with Tech2 he ramped up fuel pressure and the knock got louder and more noticable truck even stumbled a little.
Says he replaced the relief valve and still the same. Says GM Techline tells him to check the oil pump, that the gear may be spinning on the shaft, but he says this after I mention it to him.
Hopefully they will begin dropping everything tomorrow to check the pump.
Anyone have any ideas what it may be?
Knock can hardly be heard at idle and sometimes cannot be heard at idle.
Drive around the block and bring it up to temp and knock is louder with more accel or rpms. Sounds BAD sick. | 
Linear Mode
