Kinda rough idle and higher than normal idle in park.
#1
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Year: 2000
Model: Cherokee
Engine: 4.0
Kinda rough idle and higher than normal idle in park.
Hello gents, my 1998 XJ 4.0 had developed a slight miss and rough idle. This only occurs in park or neutral and it drives and performs perfectly. I get about 11 MPG, I chalk that up to me liking the skinny pedal too much. The idle also seems a little high. Normally it's about 750rpm but it's like 800-900 now. What could this be, clean air filter and the PCC components where replaced a couple months ago, the CPS was replaced a couple months ago to fix a stalling issue. I haven't changed plugs or rotor. 204,703 miles.
#3
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Year: 2000
Model: Cherokee
Engine: 4.0 I-6
Have you checked for leaks in the manifold? Mine doesn't have one, but i've noticed a number of people have a crack in their manifold where it's welded/connects to the downpipe before the cat. There's also:
- Check the manifold gasket while you're at it. Turn the car on and carefully move your hand all around the manifold and feel for puffs of air, or just listen for something that doesn't sound right. It gets super hot obviously so be careful.
- Check (might as well replace) the TPS
- Take off/clean the throttle body
- Take out and clean the IAC on the throttle body.
11 mpg seems really low, even for a heavy foot.
- Check the manifold gasket while you're at it. Turn the car on and carefully move your hand all around the manifold and feel for puffs of air, or just listen for something that doesn't sound right. It gets super hot obviously so be careful.
- Check (might as well replace) the TPS
- Take off/clean the throttle body
- Take out and clean the IAC on the throttle body.
11 mpg seems really low, even for a heavy foot.
#4
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Year: 2000
Model: Cherokee
Engine: 4.0
My manifold is broken and cracked but they where cracked and broken before this started happening. I already cleaned the TB and IAC.
Last edited by jpmarine6786; 12-09-2015 at 11:21 AM.
#6
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Year: 1997
Model: Cherokee
Engine: 4.0L
Hello gents, my 1998 XJ 4.0 had developed a slight miss and rough idle. This only occurs in park or neutral and it drives and performs perfectly. I get about 11 MPG, I chalk that up to me liking the skinny pedal too much. The idle also seems a little high. Normally it's about 750rpm but it's like 800-900 now. What could this be, clean air filter and the PCC components where replaced a couple months ago, the CPS was replaced a couple months ago to fix a stalling issue. I haven't changed plugs or rotor. 204,703 miles.
#7
CF Veteran
And difference between in Neutral or Drive?
Edit: sorry, wrong thread
Edit: sorry, wrong thread
Last edited by Roler; 01-19-2021 at 04:21 PM.
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#8
CF Veteran
Can be number of thingsI'd start with:
CLean the IAC and throttle body ( esp plate on both sides), use new gasket on tjrottlebody
If not been done recently do a tune up with fresh plugs and gapped correctly, plug wires,cap and rotorClean up your grounds
Adjust the throttle cable
these are all relatively simple and good maintenance
Let us know if this made a change.
CLean the IAC and throttle body ( esp plate on both sides), use new gasket on tjrottlebody
If not been done recently do a tune up with fresh plugs and gapped correctly, plug wires,cap and rotorClean up your grounds
Adjust the throttle cable
these are all relatively simple and good maintenance
Let us know if this made a change.
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