vtec code help and low oil pressure
 

98 accord had head gasket issue so had head machined put new gasket on the car problem solved then I get a vtec code replaced vtec solenoid with oem honda drive the car 5 miles get same code then at idle oil light comes on dim changed oil same issue went to 10-40w just a try same issue.car idle around 750 rpm in drive light doesnt come on in park only in drive Did not have this issue before changing the head gasked only had a misfire code that is cleared since head gasket change vtec code only comes up after car warms up and car runs perfect no noise any ideas? Car has only been driven 20 miles since head gasket swap its a 98 accord lx 4cyl vtec automatic transmission 150k miles

Head gasket installed upside-down?

No verified that when i installed it is marked for the up side and verified head gasket set was correct part number

Did you use any RTV on the rubber gaskets other than the corners of the arch near the camshaft?

Did you change the oil/filter after the cylinder head was installed?