misfire and flashing check engine light? 4.0 inline 6 engine


Asked by Feb 08, 2017 at 12:58 PM about the 2003 Jeep Grand Cherokee Laredo 4WD

Question type: Maintenance & Repair

Ive been getting a misfire when the engine temps gets to 210F, it will only do
this if it is idling, ounce i get the temp back down the misfire will go away, I am
thinking it is a catalytic converter based on what i have read online, It had 3
cats, 2 in the manifold and one down stream. Is the cats or something else, i
cant figure it out and i dont want to take it to shop.

6 Answers


That's what the flashing check engine light means. Random misfire. Check for codes to see where to go from here, if u keep driving it with misfires, it will plug up the catalytic. Ur misfires could be due to dirty throttle body, low fuel pressure, bad injectors among other things

1 of 1 people found this helpful.

the misfires didnt start happening until i started to put winter mix gas into, if i cat is bad which one is it? Correct me if i wrong but since it does have 3 cats does that mean it has the California emissions standards, i live in in ohio so im not really for sure.


Are you sure you have misfires? Scan for the codes as suggested above. Then you will know for sure. If you do get a misfire code, then you looking at replacing spark plugs and coils first.


So is it possible that I'm am losing spark and the unburned fuel is going into the cats causing the flashing light? It's acts like it misfiring but if I hold the rpms up for a little bit it clears up and and everything is fine agian


Something like that. Ur feeding fuel or lack of, that is not being properly burned and C02 sensors detects the inefficiency and turns check engine light on

Mine was the same problem I just found my num # 7 injector at the back pissing fuel out and it caused sunburnt fuel thru exaust and black suot on the ground at end of tail pipe

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