1999 xj wont rev past 4k rpm
03-22-2017, 08:53 AM
#1
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Model: Cherokee
1999 xj wont rev past 4k rpm
My cherokee is starting fine but after its been idiling for a while its starts sputtering sounds like a cam lope when idle obviously its not but it will drive fine down the road untill i floor it, it will cut out around 4k and wont go past ive heard this could be a fuel filter,idle air control valve, or a cam sensor just would like a opinion on what it may be before i tear this turd apart
thanks
thanks
03-22-2017, 11:20 AM
#2
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Year: 1999
Model: Cherokee
Engine: 4.0
It could be a fuel delivery (pressure/volume) issue or cam sensor (doubtful) but not IAC.
Don't rule out a defective coil. Coils do fail after heating up and/or when under load.
You can test the coil but it does require removing it to get at the pins easily. If you do this examine the coil for cracks as well.
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Remove the distributor cap and examine the rotor tab and the cap spark plug terminals. If your plug wires are old consider replacing them. If your spark plugs are old consider replacing them as well (Use NGK ZFR5N plugs).
Examine the cam sensor while you have the cap off. Examine the cam sensor wiring and connector.
Don't rule out a defective coil. Coils do fail after heating up and/or when under load.
You can test the coil but it does require removing it to get at the pins easily. If you do this examine the coil for cracks as well.
.
.
Remove the distributor cap and examine the rotor tab and the cap spark plug terminals. If your plug wires are old consider replacing them. If your spark plugs are old consider replacing them as well (Use NGK ZFR5N plugs).
Examine the cam sensor while you have the cap off. Examine the cam sensor wiring and connector.
03-22-2017, 04:51 PM
#4
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They are new
The plugs and wires are new, guy a I bought it off was a buddy of mine and said he put brand new ones on plus they look new, what would I have to check for bad fuel pressure
03-22-2017, 06:49 PM
#5
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Year: 1999
Model: Cherokee
Engine: 4.0
2. As for verifying fuel, get your mitts on a fuel pressure gauge. Some parts stores rent them; call around for availability. The connection is at the schrader valve on the fuel rail under the hood. For a 99, you need 49 psi, plus or minus 5 psi. I agree with CCKen and would get some fuel pressure testing done. Not saying that is your problem, but I am saying that it needs to be ruled in or out early in the troubleshooting process. Fuel pressure is such a critical data point.
Last edited by tjwalker; 03-22-2017 at 06:51 PM.
03-23-2017, 12:35 PM
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Year: 1998
Model: Cherokee
Engine: 4.0L
Or if you're just going to skim right past an excellent post like that, you can go fire the parts cannon at it.
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03-24-2017, 10:55 AM
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Model: Cherokee