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

Gameov3r · 09-30-2009, 07:14 PM

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

**octaneman** · 09-30-2009, 11:34 PM

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.

Gameov3r · 10-01-2009, 03:24 AM

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

Gameov3r · 10-01-2009, 05:59 PM

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. :)

09-30-2009, 07:14 PM	#1 (permalink)
Gameov3r Registered User Join Date: Sep 2009 Location: Ontario Posts: 3 OS: Vista	99 Jeep Wrangler 4.0L Rough Idle, Chugs On Acceleration. 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

09-30-2009, 11:34 PM	#2 (permalink)
octaneman Mentor Home Support, Gearhead Automotive Center Join Date: May 2009 Posts: 548 OS: WINXP	Re: 99 Jeep Wrangler 4.0L Rough Idle, Chugs On Acceleration. 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.

10-01-2009, 03:24 AM	#3 (permalink)
Gameov3r Registered User Join Date: Sep 2009 Location: Ontario Posts: 3 OS: Vista	Re: 99 Jeep Wrangler 4.0L Rough Idle, Chugs On Acceleration. 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

10-01-2009, 05:59 PM	#4 (permalink)
Gameov3r Registered User Join Date: Sep 2009 Location: Ontario Posts: 3 OS: Vista	Re: 99 Jeep Wrangler 4.0L Rough Idle, Chugs On Acceleration. 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. :)