Top 10 causes of a bad poor rough idle....
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Joined: Oct 2012
Posts: 1,744
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From: USA
Year: 1998
Model: Cherokee
Engine: 4.0L i6
Top 10 causes of a bad poor rough idle....
For the new guys, can we make a list of all the things that can cause a bad idle?
I'll try to start the initial list.
Can we sort them in the best order for the most usual culprits?
I'll try to start the initial list.
Can we sort them in the best order for the most usual culprits?
- TPS (Throttle Position Sensor)
- Idle Air Control (IAC) motor
- Vacuum leak
- MAP sensor?
- Bad battery (effects ECU)
- Clean Throttle Body? (getting stuck?)
- CPS (Crank)
- Cam PS / Distributor Pickup Switch
- Distributor cap, rotor, wires, plugs
- Low fuel pressure? (Fuel pump)
- Bad alternator ?
- O2 sensors (should throw code)
- Bad injector?
- Replace coil?
- Intake Manifold Vacuum leak?
- EGR valve?
- CCV hoses clogged?
- Fuel filter?
- Air Temperature Sensor?
- Coolant Temp. Sensor
Last edited by BimmerJeeper; Mar 26, 2014 at 07:41 PM.
CF Veteran
Joined: Apr 2009
Posts: 1,601
Likes: 1
From: Kalamazoo, MI
Year: 2000
Model: Cherokee
Engine: 4.0L with throttle body spacer and cold air intake, bored throttle body, #784 injector upgrade
21. wrong spark plugs or failing spark plugs. ( they seem to run the best on el cheapo champions )
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