90 Gxl Cold starts then stalls, Mysterious plug
 

The car ran fine before i tinkered with it by removing the UIM and LIM to get my Header gasket changed :blush:
It will cold start then fall flat on its face after the 3k warm up. Will not hold its idle. have to keep my foot down to keep it alive.
Checked for vacuum leaks but only one i found my air pump a bit loose, then decided to just remove the top the check Lines. found a mysterious black plug next to the "water thermosensor " and the primary injector plugs.
I check the FSM and the wiring FSM and for the life of me can not find wth it is. :scratch:
Could this be what was causing my probs?
can anyone help or at least point me in the right direction ?
Again, car ran fine before i touched it:blush: so it can't be a tps, bac, afm or its fast idle cams right?

Does plug have a wire? If it does what is the color of the wire(s)?

Single, Black and green

That would go to the temp switch related to the auxiliary electric fan for the cars that are equipped with them such as autos and most turbos. It's not related to your problem as your problem is most likely a vacuum leak. And you'll want to make sure the AFM didn't become unplugged.

Just double checked everything and all the lines seem to be fine. I ran the AFM unplugged and it just fired up and shut down fast. Plugged it back in, it rev to 3k then after awhile it just stalls like mentioned before. Tried to keep it at idle with my foot at 1,500k to 2k but it struggles and bounces.

umm this might or might not be the problem but before i removed the UIM it had wet spots around the holes where the gaskets goes..look like it was a leak? and maybe by me removing it, it unsealed it from all the years of being closed? sprayed Carb Cleaner in it, no rpms raised.

A visual look over is not going to confirm a leak or not.

Arighty will get to spraying stater fluid and will report back.
I'm going to find this vacuum leak weasel:egrin:

Propane torch minus the flame works good too

Found the leak!!:icon_tup:
it was the hard rubber part that meets the throttle body had a fat gap underneath that wouldn't close up with just te bolts and a cracked Primary injector.
Thank you for the help!:bowdown: i was starting to feel like pushing this car off a cliff

Good for you.