Possible effects/results of clogged flame trap include seeping leaking of oil at any seal. Wherever the seal is weakest is where oil will tend to come out. Likely places are the oil filter gasket, oil fill cap (has a flat ring rubber gasket), front seals, rear seals, cam rear seal.

I don't think it actually affects the engine performance unless you lose too much oil. But the clogged hoses and the crankcase pressure forcing oil and oil vapor into the intake system at the wrong times can't be a good thing.

I'll write about the double vacuum hose logic further down. Here's what I recommend you do.

I'd definitely take off the throttle body and all hoses to it (including the fat accordion hose), and clean them up. Check fat accordioon hose for cracks, especially on underside. Considering that the two flame trap hoses were partially/fully clogged, there's a good chance that there's an accumulation of crud in the TB's butterfly valve and also in the tb's two pinholes for the two nipple vacuum connections.

Re. cleaning the throttle body:
1) Beware of the throttle position sensor (tps) located at firewall end of t/b assembly. It's mounted via oversize holes allowing for adjustment. If you detach the tps you'll have to set the adjustment when remounting.
2) Get a t/b gasket before you start. No need for gasket sealant in my humble opinion. Sometimes you can reuse the gasket. See clening notes re. IAC below.

Similar for the idle air control [IF you have one].
Hose from iac to t/b likly coated with crud. IAC internals also likely coated with crud. I cleaned mine with carb cleaner. Can says it's NOT for fuel injected engines so make sure everything is dry before you fire it up again.

IAC location: See fat flame trap hose connection to main air intake hose. Matching fat hose connection on other side of intake hose (forward) leads to the idle air control. IAC has a second large hose going to intake manifold, and an electrical connection.

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Why a fat and a thin hose for flame trap?

Thin hose is connected downstream from t/b and fat hose is upstream. So the amount of vacuum in the two hoses is always different. This pulls air in at whichever hose has more vacuum, thru the flame trap housing and ultimately into the intake manifold.

Also to supply an appropriate amount of vacuum to the breather system during times of high and low rpms and vacuum.

Fat hose is attached upstream of the t/b. So it does not see much vacuum when throttle is closed. It does see vacuum when throttle is open so it pulls air at those times, picking up vapor from the flame trap and breather box and pulling them into the engine for combustion. I think the amount of vacuum it sees would vary with different throttle positions and engine rpm's.

Thin hose is attached downstream of the t/b. So it sees some vacuum as long as throttle is not fully open, and sees most vacuum when throttle is closed. Crack the throttle a bit and that's probably the max flow state for the small hose. Breathes through a small orifice in the connection nipple so the volume of air it can pull is limited. Appropriate because you wouldn't want to overload the engine with crankcase vapors when it's only idling.

My guess is that a car that is operated mostly at high vacuum and relatively closed throttle may not pull enough air through the F/T to keep it clean - because it's mostly breathing through the tiny orifice for the thin hose. Of course once the f/t screen gets partially clogged, it breathes less and less efficiently and so will clog up further.

Reportedly synthetic oil doesn't clog the F/T system. As always, ymmv.

Flame trap maintenance is a good excuse to open the throttle occasionally and get the rpm's up there. "What the **** are you doing?!?!" says the good wife. "I'm cleaning the flame trap, honey".

Rumors that they pay me by the word are entirely without basis in reality.

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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors, quad horns, tach, small clock. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.