P0172 Only and Something Else Interesting

Hey guys, first time posting here, I mainly browse/lurk so please be gentle. I'm sorry if I'm posting this in the wrong place.

So I bought this 96 4Runner a month or two ago for a very reasonable price. Its a 5VZ-FE SR5 4x4 with an auto trans. It runs pretty great, however it has ALWAYS thrown P0172, even after I have done the following my self:

- Oil change + filter, air filter, spark plugs(dual ground), sparkplug wires, several vacuum leaks
- Cleaned Original MAF, Replaced, then replaced again(warranty) at different intervals.
- Cleaned throttle body and intake plenum, replaced gaskets
- 1.5ish bottles of Seafoam in the tank over the course of 2 full tanks, .5 bottle sucked through break booster hose, lots of while smoke
- Replaced upstream and downstream o2 sensors, did NOT use universals
- Changed All 6 injectors, two ohm'd 12-13.0



Here is what I have done that I did before all that/believe is unrelated

- Rough Country 3" Lift Front and Rear (I know, I should've looked on any forum at least once, but i was excited and the suspension looked pretty bad, and other excuses $$$)
- New struts and coilovers on the front spacers.
- Upper and lower ball joints


This is what I know is wrong/bad

- CV axle boots are gone/shredded
- Timing belt cover
- Probably needs timing belt service
- Break service
- Diff service
- Minor body work


I'm sure there is other stuff I cant remember right now.


But then there's this. I was crawling around under it the other day and saw this.




What is going on here? that is the edge of the oil pan and the opening of the transmission. What piece is missing there? I dont know how I never noticed this before, how boned am I? There is transmission fluid in it and I made sure that it didnt have the "pink milkshake" going on when I flushed the coolant, buy beyond that I didnt look too much into the transmission.


I really like this little truck, I think its got a lot of potential, but these are the two main problems I've run into. Otherwise it runs great and EVERYTHING works. I'd really like to hear your guys' opinions on what is going on here. If anyone is interested Ill take more pictures tomorrow. Thanks for reading my essay.


TL;DR - Tell me my 4Runner is gonna be okay.

 

shot in the dark. but the oil on the transmission like that could be a rear main seal leak. the cover for the Torque converter could be found at a junk yard im sure, maybe rockauto if you could figure out what its called

 

Thanks, I'll look around at pick n pull sometime this week. How bad is that for it to be open like that? Also am i going to have to drop the transmission to put that on? The P0172 is also bothering me, but my heart sank when I saw that.

 

the code i would have erased. If it pops up again it might be worth looking into, but alot of error codes are bologna or not terribly harmful. Is it ideal? no. will it blow your motor? likely no. the cover...... i mean you dont want rocks and shit to be able to get into your bell housing so its not fantastic

 

Yeah, the code has always come back no matter how many times I've cleared it/pulled the efi fuse. I think it is actually a false rich. The sparkplugs aren't fowled or black, the exhaust isn't producing a lot of black soot or smoke. It wouldn't be such a big problem if I could get it to pass inspection, and rarely the engine will die at stoplights. I did clean the throttle body/IAC yesterday, but it wasn't really that bad.

 

The code is due to not enough oxygen in the exhaust, doesn't mean that the truck will smoke excessively, only that the ECM sees less O2 in the exhaust than it should and is trying to compensate. The key to finding out why is knowing the fuel trims, short term trim is instant feedback to the ECM, long term trim is a learned value. looking at trims is looking at a command, a negative value (-5.x) is the ECM telling the injectors less fuel, mix is rich. Positive trim is the opposite. Toyota's threshold for setting a lean or rich trouble code is +15% or -15%, anything beyond that will set a trouble code. Knowing how rich or how negative the long term trims are will help, but I know of two super common problems for running rich. 1: fuel leaking past the pressure regulator, easy to check. pull off the vacuum hose, if there is fuel in there it's bad. 2: injector not closing all the way, or leaking down. Not as easy to diagnose, may also cause a brief misfire on one cylinder after the car sits for a period of time. But there you have it a layman explanation of fuel trim.