My oil pressure gauge is high and blowing fuel line fuse in '91 GMC Sierra

SOURCE: 2004 GMC Sierra High Oil Pressure

if it is electrical oil pressure sensor I would start there. The best way to see if you have a major problem is to use a mechanical oil pressure tester. Take off the oil pressure sensor and put the mechanical tester on. The tester should come with a Gage. If it comes within your trucks oil pressure range than all is fine and replace the sending unit and see if that don't help your problem.If the tester runs high then the oil pump is bad or your cam-bearings could be the problem. But with cam-bearings you would usually get a low reading.

SOURCE: My 2003 GMC Sierra Z71

the oil pressure is always high when you start it,the oil is cold and creates a different reading.
a few things...to consider
oil pressure sender defective
too much oil
wrong oil type

Dennis Mulford

• 1055 Answers
• Posted on Jun 06, 2009

SOURCE: 1998 GMC Sierra- runs rough then stalls when

had this problem on my neighbors 98 chevy truck with the same engine !!
it turnd out too be the fuel pressure regulator,you have too pull the upper intake too replace it!!

SOURCE: 2003 GMC Sierra Knock sensor and oil pressure??

the knock sensors are located below the intake plenum,or,upper intake manifold as some call it, they screw into the lower intake, the front one is sensor 1, the rear is sensor 2. it is wise to change both if you have some miles.since you are going to be buying a gasket set to do this job.the sensors are cheaper than the gaskets.

SOURCE: LOW OIL PRESSURE ON 2007 GMC SIERRA 1500. CHANGED

have it tested using a manual gage if still low then main baring ore most likely bad that would mean a over hall if is really low and bearings bad should be making rattle noise when started up first few seconds

Testimonial: "thanks alot.truck is not making a rattling noise.we did check it with a manual gauge.it read about 10 at idol. press. gets better as you incr speed"