1993 Honda...trouble starting

My 93 Honda Civic seems to be hit-or-miss when I try to start it lately. Sometimes it starts fine, other times it makes the rr rr rr noise, but doesn’t turn over all the way. I took it to a mechanic who said the battery is good and the starter is good. He said it might be a compressor or fuel injection issue. He also said to call him when it’s actually happening, which seems pretty sketchy to me. Any ideas?

Do you notice if the problem occurs more when the interior of the vehicle is hot?

Tester

SOMETIMES(?) the engine barely turns over when you try to start? Is that the symptom? If the starter engages; but, cranks slowly sometimes, this could be the large electrical contacts inside the starter solenoid (on the starter motor) aren’t making good contact every time. Some mechanic might take the starter solenoid and file the contacts. Most, replace the whole starter (with the solenoid on it).