1990 Oldsmobile Cutlass

When the problem occurs, if it cranks good but won't start, have a helper crank it while you visually check for spark at the plugs. You can use a known good spark plug or spark tester, don't take plug out of engine. Then just pull a plug wire, stick tester in plug boot, ground metal part of tester to metal part of engine, watch for spark.

Sometimes the coolant temp sensor can cause temp related issues? Any applicable mil codes?

Some AZ stores will check obd1 also. One of my sons used to work at one. He said he would check obd1 and obd2 codes.

You use a jumper wire at the A and B terminals, data link connector. Then you turn the key just till the dash lites come on, no further, no crank. Then the mil starts flashing, you count the flashes to get the codes.