when I start my car up for the first time or after i leaved it parked for like an hour or two, when i turn the key, it cranks for like 3-4 seconds before the engine starts. Once it's started though, if I turn it off, and then try to start it again, it'll start almost instantly...

My oil pressure gauge is also inconsistent. Sometimes it's at half, sometimes a little less than half, and sometimes it's 3/4 of the way up... It always changes after I turn off and restart the engine...

Also my idle sits at 2k rpm in park, but if i shift it into any other gear it drops to ~1k....

Another thing, I calculated out my mileage, and it turned out to be ~11 mpg...

I'v recently replaced my fuel pump + filter, cleaned my MAF, replaced my air filters, replaced my o2 sensor, changed oil + filter.

What could be my problem(s)? Sometimes I get a code 33, but I checked today and all I got was code 12 so I don't know what's wrong...

My car is a 2.8L MPFI auto.