need help with misfires!
#1
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Year: 2000
Model: Cherokee
Engine: I6
need help with misfires!
I got the check engine light about a week ago and the only thing I noticed was a small rough-ness in the idle, nothing major. It runs fine, no loss of power at all. the rough idle happens all the time, even when the engine is cold. I got it scanned and pulled the codes p0300, p0302, p0303, p0305, and p0306. From what i understand its a misfire, and the cause could be a couple of things. I replaced the plugs in march after getting codes for cylinders 1,2,3,and 4 and up until last week it was fine. I read and saw that it could be the cam sensor acting up ??? didnt find any leaks either. I was hoping that you guys could help me out. from what i have searched this seems to be a pretty common thing....
thanks!
thanks!
#2
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Year: 1999
Model: Cherokee
Engine: 4.0
The key to me in all of your codes is the random misfire P0300. Whenever I see those, I suspect one "common" root cause which is then also responsible for the single cylinder misfires (P0302, P0303, P0305, P0306).
First thing I would do for this is to test fuel pressure. For a 2000, you should have 49 psi, plus or minus 5 psi. You need to start the process of elimination and fuel pressure absolutely needs to be ruled in or out early in this process.
A vacuum leak or unusually low fuel pressure could be a cause here.
First thing I would do for this is to test fuel pressure. For a 2000, you should have 49 psi, plus or minus 5 psi. You need to start the process of elimination and fuel pressure absolutely needs to be ruled in or out early in this process.
A vacuum leak or unusually low fuel pressure could be a cause here.
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