My 2005 Lexus GX470 had no leak before I took it to Jiffy Lube. They changed the oil, but now, I see a puddle of fresh oil every morning. I took it back to them 2 times, but every time they said they don't see any oil leak. I have already tried cleaning the oil pan, but with no luck. What should I do?
Step 1: Assuming the leak is coming from the drain plug, tighten it and top off your oil.
Step 2: Stop going to Jiffy Lube. :)
Use a sheet of paper under the car and check every hour to find out where the drops are.
Once you have located the source - most common will be drain plug or the oil filter - sort the leak.
PS step 2 was good !
I would visually inspect the engine. Look at it from above, see if there's any fresh oil around the sides of the engine. Do the same from underneath the engine as well.
While you're under it, try and see if there's fresh oil around the oil filter and the sump plug. Sometimes these shops don't tighten filters and plugs like they should do.
I think it's going to be likely that you find a wetness around the oil sump plug. If this is the case, see if it's tight. If it is, replace the washer (which is standard on some cars).
If it needs to be replaced, take it back to where you got it and tell them exactly where the issue is. Be present when they check. And be present while they do it. After they fix it, don't bother going there again.