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sprinkles08
sprinkles08, Chrysler/Dodge/Jeep master tech
Category: Dodge
Satisfied Customers: 22381
Experience:  ASE Master and Advanced Certified, Chrysler/Dodge/Jeep Master Certified, Trans and Hybrid Specialist
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I have random misfire on my Dakota 3.9 V6. The misfire comes

Customer Question

Hello, I have random misfire on my Dakota 3.9 V6. The misfire comes after 50mls, 150 mls or actually after 350mls. The misfire only is on the left bank , cylinder 1,3 and 5. Sometimes one cylinder ist shown, sometimes two and also all three. I changed
the distributo cap, ignition wire, spark plugs, ignition coil, all sensors like cam- and crankshaft. Also the lifters on the left bank are very noisy, ticking. So six weeks ago we replaced the lifters on the left bank and they were more quiet. But now they
are noisy again and the misfire is back. Is it one problem? Compression test was ok, also the oil pressure. Because the catalytic get worse, I made him empty, till the misfire is gone, to put an new inside. Can cou help me. I`m getting crazy. The engine has
run 150000mls and run also on liquid gas. The misfire comes under fuel and gas.
Submitted: 1 year ago.
Category: Dodge
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to Justanswer!

If the lifters on that bank are noisy and the same cylinders are misfiring that's significant. If the noise and misfiring went away after replacing the lifters but then the missing and noise returned at the same time then the two issues should be directly related. If the lifters were collapsing then the valves wouldn't open all the way which will definitely cause a misfire.

Have you removed the valve cover and ran the engine to see if the lifters on the left bank are oiling?

Customer: replied 1 year ago.
No, we have not ran the engine with an open valve cover. Should I test it?
Expert:  sprinkles08 replied 1 year ago.

If all the lifters in that bank are noisy then lack of oil is likely. Go ahead and see if they're oiling.

Customer: replied 1 year ago.
Now I`m not sure, if my friend has put in the lifter in the right way. May the whole for the oil st pointing to the other bank and not to the outside. So, I have to open everything, or?
Expert:  sprinkles08 replied 1 year ago.

If the holes in the lifters weren't turned the correct direction then they'll definitely have oiling issues.

Customer: replied 1 year ago.
Which is the correct position?
Expert:  sprinkles08 replied 1 year ago.

The holes face upward.

Customer: replied 1 year ago.
Ok. The rocker arms are oily. So oil is coming and so we have no lack of oil.
What could cause the misfire?
Today after another 130mls I had again a misfire on cylinder 3.
Expert:  sprinkles08 replied 1 year ago.

You started the engine with the valve cover off and saw a solid spray from each?

Customer: replied 1 year ago.
Customer: replied 1 year ago.
May there is no relationship between the mifire and the ticking.
Customer: replied 1 year ago.
I`m wondering cause the misfire is coming after 50, 100 or 150 mls. Or after 360mls.
Expert:  sprinkles08 replied 1 year ago.

Have you tested spark and injector pulse on the cylinders affected at the time the miss is present?

Customer: replied 1 year ago.
How should I test it? The misfire is coming once (the mil is on ), but you don`t feel the misfire. If you clear the the code, the light is off and the next miles the car is running without misfire-code.
Expert:  sprinkles08 replied 1 year ago.

Was a static or running compression test done? Do you have the results?

Customer: replied 1 year ago.
The compression test was made while the engine was idling. The result I don`t have. The test made a mechanic and he told me, everything would be ok.
Expert:  sprinkles08 replied 1 year ago.

It's likely that the engine is actually misfiring but if you don't believe there is actually a miss then you may have a failing crank sensor or the area that the sensor mounts may have enough rust buildup to move the sensor away from the flexplate. The crank sensor signal is how misfires are monitored and in rare cases I've seen a failing crank sensor set misfire codes when the engine was running smoothly. I see that the crank sensor was replaced but if it was aftermarket it's still suspect.

Otherwise if it's actually missing it's going to be a cylinder sealing issue, spark or fuel. You may have failing injectors or injectors with restricted inlet screens, localized vacuum leaks causing individual cylinders to run lean, or ignition system issues. Most of the ignition system was ruled out but if the spark plugs were damaged or incorrect there will be continued problems.

The most common cause of misfires on these if the ignition system is ruled out was valve seats, burnt valves or cracks in the head. Knowing the actual running compression test numbers would be very helpful.

Customer: replied 1 year ago.
If the valve seats would cause the misfire, then the misfire must come continously, or?
Expert:  sprinkles08 replied 1 year ago.

A seat issue would usually cause a more consistent miss.

Customer: replied 1 year ago.
what else could be cause the misfire?
Expert:  sprinkles08 replied 1 year ago.

As I mentioned possible causes for misfires are cylinder sealing issues, vacuum leaks affecting single cylinders, injectors, and the ignition system. Here is my post from this afternoon again if you didn't see the whole thing:

It's likely that the engine is actually misfiring but if you don't believe there is actually a miss then you may have a failing crank sensor or the area that the sensor mounts may have enough rust buildup to move the sensor away from the flexplate. The crank sensor signal is how misfires are monitored and in rare cases I've seen a failing crank sensor set misfire codes when the engine was running smoothly. I see that the crank sensor was replaced but if it was aftermarket it's still suspect.

Otherwise if it's actually missing it's going to be a cylinder sealing issue, spark or fuel. You may have failing injectors or injectors with restricted inlet screens, localized vacuum leaks causing individual cylinders to run lean, or ignition system issues. Most of the ignition system was ruled out but if the spark plugs were damaged or incorrect there will be continued problems.

The most common cause of misfires on these if the ignition system is ruled out was valve seats, burnt valves or cracks in the head. Knowing the actual running compression test numbers would be very helpful.