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Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Jeep
Satisfied Customers: 1516
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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1998 grand Cherokee v8 5.2 liter(replaced computer, plugs,

Customer Question

1998 grand Cherokee v8 5.2 liter(replaced computer, plugs, cap, rotor and o2sensors, fuel pressure holding steady at 48 psi, starts and idle good but as soon as the rpms reach 2500 it starts to run bad like its running out of fuel and gets worse as you demand more,
Submitted: 10 months ago.
Category: Jeep
Customer: replied 10 months ago.
you can also call me at(###) ###-####
Expert:  Juan Crespo replied 10 months ago.

Hi there. Welcome to our site.

Mopar issued TSB 18-48-98 addressing those symptoms. Click here to see the TSB.

Best Regards.

Customer: replied 10 months ago.
it still starts and idle fine and when you increase throttle, it starts to run bad still like it has no power or running out of fuel and fuel pressure still holding steady at 48 psi and you can also call me at(###) ###-####my cell
Expert:  Juan Crespo replied 10 months ago.

Did you reroute the coil and spark plug wires as indicated in the TSB?

Also, JA rules prohibit us from contacting customers on our own. If you need to talk to me, then you'll need to request the phone call through the site.

Best Regards.

Customer: replied 10 months ago.
yep i rerouted the coil and spark plug wires and it didn't change anything still when rpm are increased (2500) it acts like its running out of gas, no power and its not misfiring that i can here and when you let it return to idle it runs fine
Expert:  Juan Crespo replied 10 months ago.

Something is not right. Either the PCM is not getting the right information from the MAP and TPS; or it is getting those signals but it's not reponding by increasing injector-on time - we will need to plug in a scan tool capable of reading engine data to check that possibility. Or, we're getting fuel pressure but not the volume that we need at higher RPM. Can you check with a fuel pump tester that can test volume as well (click here to see sample)?

Customer: replied 10 months ago.
ok will check that and get back to you
Expert:  Juan Crespo replied 10 months ago.

Looking forward to it.

Best Regards.

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