Jeep: jeep pioneer, jeep connection, fuel pressure

Question
my mother in law has a 89 jeep pioneer 4x4 4.0 ltr. has in excess of 200k miles. says it will start & idle but bogs badly when given gas but if it gets up to around 45 mph its ok . they ( dealership ) can not find where to plug in the diagnostics at and it has no check engine light so they cant do the key on off diagnostics , any help would be greatly appreciated , thank you .

Answer
inthe engine compartment on the passengers side you will find a black cover just below the coolant bottle there should be 2 plugs under that black cover and they are what the crysler drb II plugs into with the jeep connection adapter. Have you checked fuel pressure With a guage or check exhaust for blockage using a vacuum guage??? the dealer should be able to check those out without a datalink connection.