Not long after I bought my 07 LTZ I had the oil pressure filter and sending unit replaced. Now after a few months it's doing it again but with a different angle. I replaced the oil and after restart it pressure went up then did the swing downward to 0. Engine purring along as normal, no sounds indicating that there is a true oil pressure problem. So this morning I moved it to get my motorcycle out to head to work I found that with the key on it would now indicated about 40psi of oil pressure with out the engine running. Started the engine and the pressure gage spikes to 80psi. Turned the engine off and restarted and it did the same thing but I noticed the 40psi with the key on now is reading 60 psi.


I did try to search more about this but for some reason the term "oil" is too short and the search feature drops it so I get 99% garbage in the results.

 

Sounds like you might be having a problem with the stepper motor for the oil pressure gauge. Chevy had a problem with theses from 03 to 06. Yours might have been at the tail end of the 06 problem. To be certain you can try a mechanical oil pressure gauge to verify if you are getting accurate readings. If it is the stepper motor then you might as well change all 6 of them as they will all probably go bad eventually.

 

see TSB PIP4786A 4/10/2015

 

Yes, that is the common one with low pressure, but the high pressure doesn't fit this TSB that I can see.

 

I would be suspecting a cluster issue also by the sounds of it. You need to get ahold of a scanner and mechanical gauge to be sure though.

 

Tanin Auto Electronix here! We are vendors on the site and want to offer some assistance. It is really impossible to diagnose over the internet and without seeing the cluster, but if you determine that the issues are in the cluster, check out this link for more info on our diagnostics service. We can repair the cluster for you with a fast turn around time!

Gauge Cluster Speedometer Diagnosis Service

Let us know if you have any questions at all.