# 99 Jeep Wrangler 4.0L Rough Idle, Chugs On Acceleration.



## Gameov3r (Oct 1, 2009)

1999 Jeep Wrangler 4.0L 5 Speed, Runs Rough And Will Pop And Chug Under Acceleration, Under 3000 RPM. Sounds Like Vacuum Leak With Surging RPM At Idle, But There Are No Vacuum Leaks And No DTC's. I Have Changed The Plugs, Wires, Cap, Rotor, And Crank Sensor, Problem Is Still There. Any Ideas?? Please Help!!

Thank You,
Adam


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## octaneman (May 13, 2009)

Hi Gameov3r

Have the map sensor tested for the sensor's VREF 5 volts to see if it's open or shorted, also have the throttle position sensor tested with a DVOM dead spots while pushing on the accelerator. Clean and repair any broken , loose, corroded ground wires on the harness leading to the ECM and the surrounding sensors. Hook hook up a fuel pressure tester and test the fuel pump to see if it's within specs.

post back your findings.


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## Gameov3r (Oct 1, 2009)

Hi Octaneman Thank You For Your Reply, I Have Tested The TPS With Both A Scanner And A DVOM And It Tested Out Fine, No Dead Spots Or 0v. I Have Not Checked The MAP But That Is Now My Next Step, Along With A Pressure Gauge For The Fuel Pressure, Many Thank's Will Respond With Results Soon.

Thank's Again


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## Gameov3r (Oct 1, 2009)

I Got It! Thank's To A Member On www.wranglerforum.com He Suggested The Upstream O2 Along With Many Things, And That Was It, Thank You For Your Help Regardless.


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