Mechanics

RANDOM MISFIRE CODES AND SOLUTION TO FIX PROBLEM

1999 Isuzu Trooper • 183,100 miles

My trooper is missing when you accelerate sitting still and driving. Misses when you go up a hill, so bad that you have to get off the road. You let off the gas it idles find. When you idle it up it starts bogging down and spatting real bad also check engine light comes on. It acts like its not getting enough fire or out of time, but it go back to idling fine. I took it to advance auto they checked the codes it read PO300 random / multiple cylinder misfire detected. You can only get to 45 MPH and 2000 - 2100 RPMs before the motor starts rattling. I have changed the spark plugs and coil boots, however it didn't fix the problem. Any suggestions on what to check next?
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Audgec
September 29, 2012.




Have you checked the egr valve yet?

Saturntech9
Sep 29, 2012.
I checked the EGR valve, don't think it was the EGR valve. Replaced it, still had the same problem.
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Tiny
Audgec
Nov 7, 2012.
Have you done a back pressure test yet?

Saturntech9
Nov 7, 2012.

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