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Toyota Repair/1989 Toyota Corolla/ Smog Issues, possible Carburetor?

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Question
Original owner of 1989 Toyota Corolla- L4 Cyl 1.6- Automatic transmission.
Recently failed smog test in low mileage (15mph) by narrow margin in HC (ppm) category
Max: 134 Measure: 154.

Without any further diagnostics done yet, to determine cause of the issue/problem that is causing these numbers to be off, (and non passing smog test for the first time!)

I've been told that it could be various factors causing this situation, which without further evaluative diagnostics, would be difficult to determine whether it is an actual carburetor/carburation issue?

(Which if it is, is also problematic, since the age/make/model of this car doesn't necessarily lend to easy repairs, rebuilds or replacement?)

(True/untrue?)

I'm wondering what if any assessments, suggestions an expert may have, for me to try and address this situation, (get my car to pass,) and also directly pursue the most cost efficient way of remedying/addressing this current issue?

Mileage on the car is at @196, 400....
Well maintained throughout the years.

Did just have a new muffler put on today, before taking it to the smog shop where the car failed*
:(((

But other than that, I haven't had any major recent repairs.

(Broken part in the differential/transmission repaired/replaced @2 years ago...)
I believe a new catalytic converter sometime in the last 5-7 years.
And the only other existing problem I know of is an oil leak, that has progressed, to where it could be more than the pan gasket leaking, could be front engine seals?  (But that is also a substantial repair, that I have left unattended, while just manually checking/adding oil as needed.)

Is there any way to point me in the best/right direction as far as the current smog test failing- (passed every other aspect, and car is not a gross polluter by any means-)
And is there any way to know whether or not it is worth it to address any carburetor work/repair or adjustments- as a clear factor to why the car is currently failing emissions test or could it truly be other possible problems that should be checked out/diagnosed first?

Apparently since any carburetor work done, (if I can even find anyone who does this work for this old of a part, on this car specifically-) isn't guaranteed even after the repair to enable the car to pass smog...

I'd appreciate any efficient advice as to how to approach this problem in the most expedient and cost effective manner possible.

Thank you!

S.

Answer
Hello, higher than normal HC emissions are always due to incomplete combustion, causing some unburned fuel to come out in the exhaust gas as excessive hydrocarbons, this can be caused by a slight misfire, or a carburetor issue as you have mentioned, in your case it is a small amount over the limit, before doing anything I would recommend that you go to an autoparts store like O'Reillys, Autozone etc and purchase a fuel additive and add it to the gas tank per instructions, they have a couple of products that even guarantee to pass smog or you get your money back, do this just before going back to the test station, drive the car on the highway about 20 minutes or so, I don't know what state you are in but most smog stations will agree to do a pre check before doing the actual test to make sure it passes.

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