Strange bog/misfiring going on; and some newbie questions.

[Ly7h3n]

Hey everyone! Ive been lurking around here for awhile, but havent needed to post anything until now. Was hoping I could get help/advice for my '91 Talon Tsi (Awd)

My first issue is quite strange. My car starts and drives absolutely fine when its cold or has sat for a few hours. No issues as it comes up to opertating temperature either. However, if I drive it then let it sit for 20min-1hr (not fully cooled down) and then try to drive it, the idle sounds really rough, it bogs, and missfires. The turbo still spools just fine when this happens, but it makes zero power and "bucks" back at me when I try to accelerate (even slightly). From a stop, as I release the clutch, I pretty much have to go WoT in order to keep it alive and get the car to move. Any idea as to what could be causing this?

As far as the newbie questions go; I was wondering if someone could help me indentify a few things in my engine bay. Ive searched and have a haynes manual, and still got nothing. First is this electrical plug on top of the trans; it was disconnected when I bought the car and plugging it in seems to do nothing. What is it?

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Second newbie question is what is this? Its right behind the radiator and seems to be part of the power steering or oil system maybe? Just wondering what it is and where it should be...Im assuming it being zip-tied in that location is all sorts of wrong .

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[russell3123]

In the second picture it looks like youre oil sending unit.It looks like some one ran a t off youre oil housing so they could run a stock and aftermarket oil pressure gauge.

 

[SrKegler]

Pic one is the reverse switch for the back up lights. Second looks like it may be the wire that plugs into your power steering pump.

 

[zcox122]

Second pic appears to be the oil sending unit.

 

[SrKegler]

Pic 1. Reverse switch for back up lights. Pic 2 could be the wire that plugs into your power steering pump. Other problem sounds like boost leaks, tune up, pull the plugs and Check their condition.

 

[timsgsx]

Did you check for a boost leak? I would do a boost leak test first, just to rule that out. I agree that the second pic looks like your oil pressure sending unit.

 

[ALynch]

Boost leak test, compression test just to make sure everything is kosher, and while you're at it, throw some new plugs in.

 

[Ly7h3n]

Thanks for the replies everyone. Good call on identifying my reverse light switch and T'd oil pressure sensor, really appreciate it! My car is going into the shop early next week and Im getting new plugs,wires, and fuel filter...Ill report back if that seems to fix it. Suppose I should also look into a compression check and boost leak test as well. I was briefly looking up the boost leak procedure and it seems really simple, except for something about needing the engine at a certain position (something about valves being in correct position?). Do I need to worry about that; if so can that be achieved by turning the crank by hand and how do I know its in the correct position? Thanks again for the help everyone!!