Engine wants to try to die above 40mph Help!
#1
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Year: 1999
Model: Cherokee
Engine: 4.0
Engine wants to try to die above 40mph Help!
all seems ok until it hits around 40 mph, then it's like it wants to bog down, or no power, or try to die...
Anyone have an idea?
TIA
Anyone have an idea?
TIA
#2
CF Veteran
Sounds like airflow starvation. Need to ask dumb questions now. What's the status of your typical/standard owner maintenance items? When was your last tune-up with air filter, throttle body cleaning, plugs, cap, wires, OBD readbacks, etc....
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Year: 1999
Model: Cherokee
Engine: 4.0
First two things that come to mind are a fuel delivery problem and a clogged catalytic converter.
1. Verify fuel pressure with a fuel pressure gauge installed on the schrader valve on the fuel rail. At idle, you should have 49 psi, plus or minus 5 psi
2. Verify that you have no exhaust restriction with a vacuum gauge. SEARCH for how to do this.
1. Verify fuel pressure with a fuel pressure gauge installed on the schrader valve on the fuel rail. At idle, you should have 49 psi, plus or minus 5 psi
2. Verify that you have no exhaust restriction with a vacuum gauge. SEARCH for how to do this.
#5
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Year: 1999
Model: Cherokee
Engine: 4.0
Tune-up..dunno Air filter...I took out few weeks ago and it looked fine
Throttle body cleaning...dunno plugs...dunno cap...dunno wires...dunno OBD readbacks? wth? lol
It is throwing a code, so my son is going to take it to school Mon to see what code it is. They have a really nice garage for Autotech class.
#6
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Year: 1999
Model: Cherokee
Engine: 4.0
First two things that come to mind are a fuel delivery problem and a clogged catalytic converter.
1. Verify fuel pressure with a fuel pressure gauge installed on the schrader valve on the fuel rail. At idle, you should have 49 psi, plus or minus 5 psi
2. Verify that you have no exhaust restriction with a vacuum gauge. SEARCH for how to do this.
1. Verify fuel pressure with a fuel pressure gauge installed on the schrader valve on the fuel rail. At idle, you should have 49 psi, plus or minus 5 psi
2. Verify that you have no exhaust restriction with a vacuum gauge. SEARCH for how to do this.
After doing some reading on here, I am wondering if it's not he Cat...seems like similar syptoms... would it throw a code?
I'll have my son run those test at school?
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#14
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Year: 1992
Model: Cherokee
Engine: 4.0
a cat will usually throw a code not always. these jeeps are known for havin bad cats. usually if the truck runnin bad ruined the cat it will throw a code but if the brick is broke i see them alot without codes. we prolly put 2 or 3 cats on cherokees every moth at work. normally runs between $200-$250
#15
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Year: 1990
Model: Cherokee
Engine: 4.0L
fuel filter
im thinking it will be your fuel filter,and yes it would give you a missfire code of the last 3 cylinders,but not always,hope it works out good.