Hello. I have an oil leak that I'm trying to trace down. Here's a picture of cardboard I placed under the engine (car is on ramps right now). The oil is relatively fresh oil, correct consistency and no odors or gritty feel. It is leaking on revving the engine. No leaks at idle. The main leak is to the rear of the engine (there's also a smaller leak on the driver side). The reason for 2 puddles is because I moved the cardboard forward and did a 10 count rev at approx 3000 RPM to show how much oil is leaked (the furthest puddle (top one) is the result of the test). The underside of the car is very oily, with a lot of soot. My guess is that it's been leaking a while (I just bought it recently). All the splatter on the cardboard is me trying to clean off the engine underside. What are some ideas?
I don't believe it's a HG issue because there are no other symptoms relating (oil is fine, coolant doesn't have bubbles/frothy appearance, no oil/coolant mixing, no issues with exhaust color, no noticeable issues with spark plugs after pulling all 4). There are 2 separate issues that I think might be related to this issue. At about 5500 RPM, the temperature indicator drops to cold. Prior to and after 5500 RPM the indicator is at the "normal" 1/2 position. The other issue is a CEL P0420 that occasionally trips. I reset the computer and it doesn't always come on. I think it comes on when it's really hot outside or after the engine has been running a while. I don't think it's a faulty catalytic converter because I had it smogged recently (CA emissions requirement on title change) and it tested fine. The HC's were a little high, but NOx, O2, and CO2 were well within the norm (almost at the average).
Anyhow... I'd appreciate some pointers.

 

that,uch looks like a seal.

 

Cardboard doesn't tell me or you anything. Clean the engine, or dry off, all oil. Top off your engine properly. Run it again but this time get a flash light and look for the leak.