Stomp test/TPS/Throttle shaft bearing/Valve stem woes - what's my best bet?

[Maybe Magpie]

Hi all. I attempted to do a stomp test on my car repeatedly to see if there was anything I should address that it could tell me, and couldn't get it to work. I did some research and it turns out that it's a common symptom of a busted TPS. I looked under my throttle body assembly to see that yup, the TPS was soaked in oil and apparently they don't like that. I did a quick test by pulling the throttle cable by hand after reading some R3V posts, the TPS does the first click that it should normally (basically the moment you move it) but the second click at like 70-90% is so quiet I could barely hear it, so it might be toast. I hunted for the source of the oil and it seems that my throttle assembly's shaft bearings (for the shaft that holds the butterfly itself) are leaking oil from what I think is blowby. I did some more research on THAT and it's a common symptom of worn valve seals. It also explains why my old sparkplugs were kinda oily when I changed them out during the summer.

I know if I just replace or refurb the TPS it'll get oily again fast, and while I might be able to get my throttle assembly rebuilt by a local vintage German shop I trust (for fine work I don't mind handing it off) that wouldn't solve the blowby so I'm not sure it'd totally address the root issue. My car needs a valve adjustment anyway, and while I was planning on doing that myself, my thought was if they have to mess with the head above my paygrade to address the stem seals I might as well get the valves adjusted by them while they're at it. My E30 is my primary vice but I've got a limited budget so that being a fat stack of labor hours is a bit of a bummer. Two sidenote things I'm not clear on: 1. Can you do the stem seals with the head still on the block? I imagine not but if so I might just buy the spring compressor tools and such myself. 2. My car's an autotragic (I know, I know) and while the RealOEM diagram says the TPSes are different between it and the manual, the parts I find online for sale look different from the one on my car, which in turn looks identical to the manual version as far as I can tell from the angles I could see it. Maybe one of the POs put the wrong TPS on or I'm blind. Any suggestions there are helpful.

My main question is what do you folks think'd get me the most for my money here; do the valve adjustment myself and defer the stem seals until the head needs more extensive work and just put that money towards a throttle assembly rebuild with better compatible INA needle bearings, and new TPS + some upgraded ICV and TB elbow fittings, or get the stem seals and valves done first and worry about the throttle stuff for when I have some more money? The car runs, it just tends to be a smidge grumpy at cold-start. Thanks in advance.

[It's Soda Not Pop]

What kind of mileage is on your M20? Also the TPS gets oily from the PCV hose going into the throttle body. I would just replace the TPS. It might be time for a refresh on everything. If not the bottom end at least the head needs new seals and a adjustment. Doing a valve adjust is pretty easy.

[It's Soda Not Pop]

My car also hates the cold. It always has hard start when it's cold out (below 40). Normally I just let it warm up a bit and it drives fine.

[Maybe Magpie]

What kind of mileage is on your M20? Also the TPS gets oily from the PCV hose going into the throttle body. I would just replace the TPS. It might be time for a refresh on everything. If not the bottom end at least the head needs new seals and a adjustment. Doing a valve adjust is pretty easy.

It stands about 118kish, I've put on 4k or so of that since I bought the car at 114k. I don't drive every day and it's mostly local when I do but it IS regular. I still make sure to get some time across the powerband and some highway miles on it every so often though. A lot's been refreshed on this car already - Head resurface + gasket and water pump, timing belt, coolant flush, distributor cap, spark leads, fan clutch and fuel lines are done recently throughout 2020. A bunch of other vacuum rubber e.g. AFM to TB elbow among others also. I didn't specify valve stems too because I was too novice to know to at the time and it wasn't a full head rebuild - I've been doing a whole lot of research since and working my way up complexity in terms of DIY (hood strut to window regulator so far). Since then also a new oil pan seal and valve cover gasket, there's a leak from the rear main seal but it's a very slow one and that's beyond my wallet or ability at the moment. I don't think any bearings or piston rings have been done yet but there's been no unicorn dust in my oil to speak of. The cam and rockers looked to be in good shape but the little rubber rocker shaft blocks are something I plan to replace with the valve adjustment, I didn't have fresh ones on hand then. I followed the Bentley manual on the valve cover for torque specs and pattern, I have another valve cover gasket on hand for when the valves get addressed. I know I should have done the valves then but I'm a novice flying solo and got intimidated, haha.

Smoke test didn't seem to return any vacuum leaks as of a couple weeks ago but SOMETHING'S leaking oil, clearly - I'll check the PCV too tomorrow before I head off for errands, thanks for the tip. My concern about just replacing the TPS is the same leak taking another out and I'd rather not chew through them. I'll double-check the source of the leak and if it is the PCV hose I'll get that taken care of then replace the TPS. RE: Coldstart, my car's had a slow one nearly regardless of ambient temp since before I bought it, I've just been dealing with it because it starts consistently even if it's slow by E30 standard (it was enough to be noted in its listing when I bought it).

I appreciate the advice!

[It's Soda Not Pop]

Many others have had the oil residue in the throttle body and TPS. You can also try spraying it out with brake clean or contact cleaner. Due to the PCV hose and the TB pulling in the crank case vapor this will happen after while.

[Maybe Magpie]

Many others have had the oil residue in the throttle body and TPS. You can also try spraying it out with brake clean or contact cleaner. Due to the PCV hose and the TB pulling in the crank case vapor this will happen after while.

Yup, that's what I'm planning to do once I determine the source of the leak: Fix it, then clean out the TPS and see if it works properly again, if not replacement time and move forward from there. Thanks for the clues!