Jeep Cherokee 4.0L "Code P0300" -
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Unread 09-23-2008, 01:03 AM   #1
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2000 FSJ Cherokee 
Join Date: Apr 2008
Location: Ewa Beach, HI
Posts: 5
Jeep Cherokee 4.0L "Code P0300"

Hi everyone - Greatly appreciate anyone help with your comments on possible fix to this error code P0300 that was determined by car repair shop after hooking up into scanner.

History how this came about was about few months ago were I had the check engine came on. I took it to Good Year Auto Repair Shop they replace the spark plug coils and the spark plugs because of missed firings and also replaced the gas cap (error code P0300). The jeep was running good until 3 to 4 weeks later the engine came back on. Took the jeep back to the same repair shop could not find enything but they did clean the fuel injection with no cost to me.

My wife picked up the car drove it to do errans. while driving the jeep, the jeep engine light came on then shotly there after the jeep stoled on her. She had it towed at the Jeep repair shop because it happened to be near by. The Jeep repair shop checked and could not find why the engine light came on but did said the after market battery reading low amp need to be replaced and so I replaced battery. This cost me 218 dollars just to hook up into scanner this not include the battery . I asked to have cost lowered cause they could not tell me what is wrong and should not be charged that much but I was not successful. Picked up the Jeep and then 1 month later the engine light came back on again. So took it back to the Jeep repair shop since they charged me for the same problem when I took it there the first time. But no they wanted to charge me again to check my Jeep. I was very......mad why they are charging me again. So I left there angry... but I will report them to business beareu.

Sorry, I wish I could have written the history a little shorter.

I still have the engine light on but will take my jeep back to the Good Year car repair shop tommorrow. Hopefully they can find out the cause and fix of the problem/error code P0300.

Thank you for your assistance,

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Unread 09-23-2008, 04:49 PM   #2
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2001 TJ Wrangler 
Join Date: Oct 2007
Location: Whitman, MA
Posts: 85

Hope that helps you out
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Unread 09-23-2008, 10:43 PM   #3
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2000 FSJ Cherokee 
Join Date: Apr 2008
Location: Ewa Beach, HI
Posts: 5
Thanks! I'll check out this site.

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Unread 09-24-2008, 12:22 AM   #4
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1999 XJ Cherokee 
Join Date: Jan 2007
Location: SK, Canada
Posts: 537
P0300 is a Radnom/multiple misfire...

Maybe a CKP sensor intermittantly faulty? Bad coil, what kind of spark plugs, wires and coil were put in. CMP sensor could also intermittantly be faulty as well.

As for being mad about having to pay twice for diagnosis, that is fair. Your paying for a licened tech. to spend his time looking at your vehicle. Maybe a reduced rate would be more understandable but free, hah. Do you go to your dentist and get a cavity filled and go back 1 month later and demand he fill another cavity for free cause you were there a month earlier for a previous cavity...?
1999 Jeep Cherokee SE l 4.0 HO l AW4 l NP231
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