1996 Jeep Grand Cherokee Starting Issue with P1391 Code - Intermittent Cranking and Engine Stutter

I own a 1996 Jeep Grand Cherokee with a 6-cylinder engine, 115,000 miles, and an automatic transmission. Recently, I've been experiencing intermittent starting problems. The vehicle will crank repeatedly but fail to start, sometimes requiring minutes or even overnight before it finally starts. Once started, it runs normally without any stalling. During operation, the engine occasionally dies for a second before recovering—this does not happen when idling. There is no Check Engine Light illumination, and only one instance of a P1390 diagnostic code was recorded. The issue has become more frequent over time. I have already replaced the fuel filter and cleaned both the camshaft and crankshaft sensor connectors, but the problem persists. I'm seeking advice on potential causes and solutions to resolve this recurring starting failure.