1998 Jeep Cherokee loses rpm

Dear Doctor: I have a well-maintained 1998 Jeep Cherokee with 110,000 miles. Almost every time I start and drive about half a mile, the engine acts like it’s starving for gas. It loses rpm and pops back through the air cleaner. This goes on for a few minutes and then runs fine. I’ve had the fuel pump assembly (in the tank) changed and the distributor cap and rotor replaced, along with spark plugs. I replaced all six fuel injectors and had a pressure test done on fuel rail (of course it was not acting up at the time). Could something be shutting off power to fuel pump? Don


Dear Don: You will need to take the Jeep to a repair shop and have a scan tool monitor and fuel pressure tester connected to monitor all input sensors. The first step will be to turn the key to the “on” position and check fuel pressure and input sensor value. The next step is start the engine and monitor sensors and fuel pressure. Then go for a ride while the passenger monitors the scan tool and fuel pressure. When engine acts up the monitor record button should be hit. Return to the shop where they will review the sensors leading up to the event and after the event. — Junior Damato, Motor Matters

 

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