It sounds like it's just dirt in there hanging ip the spring return of the advance. It's easy to clean as mantioned in another post. take out the breaker plate which is three screws on the side (two of them is the clip screw IIRC). Pretty straightforward, not needing an expert to rebuild unless there is obvious shaft play, which can be forgotten if you get the Crane/Allison LED ign instead of points.
For the filters, get fid of that air box for the SU's! Get two K&N elements for an '83 Corolla (these are the largest that I could find that fit under the hood) which are round and tall filters and make up two pair of round 12 gage sheet metal plates w/ the three bolt config the SU's have, some long 5/16 bolts from Home Depot and six sections of 1/2" steel tubing to fit between the top and bottom plate. Add a brass hose barb to each set, one for the valve cover breather hose, one for the crankcase breather hose (plug the nipple hole in the manifold) This will be the best intake set-up you can get for those SU's even better than what K&N makes for them as a cold air intake set-up.
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'89 245 Sportwagon, '04 V70 2.5T Sportwagon