When I first start my Blazer my oil pressure is at 40 after the truck warms up it drops to 20 and when I stop it drops to 0 and the check engine light comes on. I have taken it to two shops (one a chevy dealer) and they say they can't see what I am talking about. Anyone have any suggestions?

 

are there any unusual noises coming from the engine? could be bad pump, worn bearings. did you change the oil recently? did this happen after any work was done to the truck or slowly progressed?

 

I recently had the valve cover gasket and intake manifold gasket changed. they also changed the oil at the same time. I noticed it after the work was done. There is no noise in the engine.

 

You need to connect a manual oil pressure gauge to the sending unit connector to verify whether this is actually happening or if it's the dash gauge acting up.

 

Thank you for taking the time to help. I will have it looked at.