Thatís a little unusual. My two guess are: fuel pump or output speed sensor.
Pull the codes
Extracting Fault Codes:
Turn the ignition switch ON, OFF, ON, OFF, ON and observe the CHECK ENGINE LIGHT. The CHECK ENGINE LIGHT should begin to flash a series of codes. The flashes will be separated by short and long pauses. The long pauses separate the "ones" and "tens" positions, and each code from the next. A code 55 will be displayed at the end of the test.
94 Black Laredo 4-Liter with QuadraTrac (42RE trans & NP249 TC) 200,000 + miles purchased new
88 Cherokee 2-door with 5speed manual 139K miles(deceased) purchased new