Hey guys,

I have a 2000 Automatic daily driver with 144K now on the ODO.

So about a week ago, I had traveled about 165miles on a road trip. When I got to my destination I noticed that, at a four way stop, the idle went down and the engine idled a bit rough. I popped the hood and could hear a vacuum leak on the passenger side. Sure enough, a couple more short drives around town and the check engine light came on. Codes were lean fuel on bank 1 & 2. Upon getting the car back home, I quickly discovered that the flimsy rubber hose connecting the PCV valve to the intake had a small split and had sprung a leak. I replaced it with a short section of fuel line, much thicker wall hose and more durable. I installed hose clamps on each end and replaced the PCV valve while I was at it, even though the old one still sounded "free", making a clicking sound when I shook it back and forth.

Thinking this was going to fix everything, I cleared the codes and took it for a drive. Now the idle, when you come to a stop or put the car into gear, dips down to 400RPM and there's a lot of vibration from the engine.
Then a second or two later, it starts gradually creeping back up to the normal 600RPM and holds. It does not misfire at all, even at 400RPM like it did when the vacuum hose was leaking. No engine light or codes are coming up related to anything that could be a vacuum or pressure leak.

Upon further inspection, I noticed that the rubber boot on the air intake had slipped off the MAF sensor. It was a bitch getting it back on. I think I hit hard on a driveway (even with roller wheels mounted underneath) on the road trip and must've bent the entire radiator support bracket up just a hair, because now the boot doesn't want to slip on to the MAF sensor like it used to without taking the whole damn air box out and getting it mounted on there good and tight and then reinstalling the whole thing (air intake, MAF sensor, & air box) as a unit. I used to just be able to take the air intake off and slip it back on no problem. The boot is getting worn and, of course, it's discontinued now.

Even after fixing the boot to MAF issue, it's still doing the same thing. I can't hear any other vacuum leaks and inspection of the hoses doesn't lead me to believe that's the problem. It wasn't doing this dip down to 400RPM when put into a gear or coming to a stop before the faulty PCV hose, so I don't know why it's still doing it now.

I haven't run a vacuum check on it with a meter because I don't have one at the moment.

Any input, insight, help with this issue is appreciated.