How many fuel injectors does a 2004 Jeep Grand Cherokee Overland

find noise location first. never ignore noise on machines. and 10x that on man movers. 100x that in the air.

then scan it. using any obd2 scan tool,
a tool that does Jeep factory codes. 10x that.

have them check the fuel injectors and comprission test the engine ask the genral mgr what kinda techs he has that cant find a mis fire

If its an after market GPS then it shouldn't matter. your GPS is junk

Turn off the AC system and see if this stops, it may be due to the AC compressor cycling rapidly due to a low charge of refrigerant..

try switching with another coil from a cylinder that is working fine if it fixes prob. then replace coil. if not try checking the fuel injector by unplugging connector at injector

CHECK OR REPLACE ALL VACUUM HOSES.REPLACE AIR FILTER,REPLACE FUEL FILTER,CLEAN FUEL INJECTORS WITH A CAN OF SEAFOAM TO 3/4 TO FULL TANK OF GAS.CLEAN THE THROTTLE BODY THROTTLE PLATE.SPRAY CARBURETOR CLEANER INTO THROTTLE BODY BREAK CARBON BUILD UP AROUND THROTTLE PLATE AND SPRAY CARB CLEANER AROUND THROTTLE BODY SHAFT AREA REMOVE CARBON BUILD UP TO PREVENT SHAFT FROM BINDIND.BECAREFUL NOT TO GET CARBURETOR CLEANER IN THE IDLE AIR CONTROL VALVE AND OTHER ELECTRICAL PARTS.REPLACE ALL VACUUM HOSES ON THE INTAKE MANIFOLD AND REPLACE PCV.

it mostlikely your tire psi light.

blend doors are located in the heater box behind the dashboard.. if you are having heating problems because of faulty blend doors, try heatertreater.com they have a permently quick fix solution that really does work. i have fitted quite a few with no problems, even better heat than standard jeep blend doors..
hope this helps

Can you check that injector for pulse . May be bad wiring to pcm

I had a similar problem with my 2004 Jeep Grand Cherokee. It turned out that the battery posts and cables were corroded. I cleaned them up and it solved the problem immediately. Something to check on before you spend the money on a new battery anyway!