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have a po306 code in a 1997 f150 have replaced the coil pack…

have a po306 code...
have a po306 code in a 1997 f150 have replaced the coil pack wire and plugs also changed the catalytic converter on that side . vehicle is somewhat undered powered and it tends to backfire when coming off the line but gets better as you speed up . but it still isnt running right . the check engine light was flashing and it was really bad before i changed out the converter it lost power going uphill and was backfire also .
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Answered in 4 minutes by:
3/7/2013
Ford Mechanic: Chris (aka- Moose), Ford Technician replied 9 years ago
Chris (aka- Moose)
Chris (aka- Moose), Ford Technician
Category: Ford
Satisfied Customers: 76,953
Experience: 24 years of experience diagnosing & repairing
Verified

Hi, I’m Chris. Welcome and thanks for asking your question!

 

Which engine do you have?

Have you ran a cylinder compression test on each cylinder on the drivers side head?

 

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Customer reply replied 9 years ago

4.2 v6 not yet

Ford Mechanic: Chris (aka- Moose), Ford Technician replied 9 years ago

After these previous repairs, and the codes were cleared are you still flagging the same cylinder with a concern?

 

Are you sure you have the firing order on the coil correct?

 

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Customer reply replied 9 years ago


that code is still showing up and the wires are correct

Ford Mechanic: Chris (aka- Moose), Ford Technician replied 9 years ago

Have you verified the spark output is equal to the others, good and vibrant blue, you need to do this at the plug not the wire nor coil?

 

Have you moved the injector to see if the misfire code follows?

 

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Customer reply replied 9 years ago

not able to without removing the intake manifold so the book says

Ford Mechanic: Chris (aka- Moose), Ford Technician replied 9 years ago

The intake does not need to be removed to move an injector nor to check ignition spark.

 

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Customer reply replied 9 years ago

how do you remove it without taking off the plenum

Ford Mechanic: Chris (aka- Moose), Ford Technician replied 9 years ago

What are you needing help removing, the spark plugs or the injectors?

 

Do you have the large bulky style upper intake, if so the injectors can not be accessed wit h the upper intake place. If you do not then the injector rail can be unbolted and lifted just enough to get the injector out.

 

Prior to checking for injector issues, having a compression test ran is the first choice.

 

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Customer reply replied 9 years ago

have the large one , is there anything else that could be a problem like the pcm or any other sensore that you can think of

Ford Mechanic: Chris (aka- Moose), Ford Technician replied 9 years ago

This is not a sensor issue most likely. It can be the PCM but we would need to swap injectors or test them to verify.

 

Can you check the spark and compression for me at some point, then I can rule out a few things and narrow this down more?

 

 

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Customer reply replied 9 years ago

wont be able to check the compression until the morning can i get back to you tomorrow some time , put the timing light on the plug wires they were all firing about the same

Ford Mechanic: Chris (aka- Moose), Ford Technician replied 9 years ago

I need to verify the plugs are sparking well enough, not just the fact that they are firing. yes please do reply whenever tomorrow, I will be online about 2pm to midnight.

 

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Customer reply replied 9 years ago

What's the best way to check the plug to see if it's Park.

Customer reply replied 9 years ago

checked compression no4 170 no5 180 no6 battery was starting to run low but it was still 150 , spark was yellow on 5 and 6 but it jumped a inch to the exhaust mainfold on both of them . got a good shock from no 6 plug . took truck out for a spin still running a little rough and it tended to backfire after letting off the gas and then hitting it again . a/c clutch is engauging then shutting off on its own , and the seat belt light is flashing even if you have it on ..

Customer reply replied 9 years ago
Relist: Other.
wasnt able to provide all the information at the time to the expert needed to do a compression test and check the spark intensity of the spark plugs
Ford Mechanic: POWERSTROKE, Ford Mechanic replied 9 years ago
POWERSTROKE
POWERSTROKE, Ford Mechanic
Category: Ford
Satisfied Customers: 1,065
Experience: FORD DIESEL MASTER CERTIFIED, GAS ENGINE MASTER
Verified

Hello Just Answer customer- I am a Ford Diesel Master Certified Technician. I am here to help you repair your vehicle. Try this first, remove the vacuum line to the egr valve and just hold it to the valve while slowly bringing the rpms up to about 1200-1500 rpm. You should feel the misfire, once you do remove the vacuum line from the egr valve and see if the misfire goes away.If so The problem you are having is the egr ports inside the lower intake are plugged up except for #6. When the egr gas flows it can only enter #6 cylinder causing it to lean misfire. You will need to remove the upper plastic intake manifold to gain access to the lower aluminum manifold. Once there you will see a round tube with holes in it for each cylinder. You need to use a small pick to push the carbon out of the hole then use a blow gun to put air into the tube to blow all the carbon out. Before reinstalling the upper intake replace the lower gaskets and the isolator bolts that hold the intake to the lower intake. Let me know how you make out.

POWERSTROKE
POWERSTROKE, Ford Mechanic
Category: Ford
Satisfied Customers: 1,065
Experience: FORD DIESEL MASTER CERTIFIED, GAS ENGINE MASTER
Verified
POWERSTROKE and 87 other Ford Specialists are ready to help you
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Customer reply replied 9 years ago

it has an aluminum upper manifiold not plasic does your answer still apply 4,2 l v6 , will driving the vehicle screw up the engine or cataltic converter

Ford Mechanic: POWERSTROKE, Ford Mechanic replied 9 years ago
yes it still applies. The egr passage is in the lower intake. Not unless the check engine light starts flashing. Thats a type A misfire and can damage the cats. Just do the test I described earlier to make sure that is the issue. It's a very common problem with the 4.2 engine.
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Customer reply replied 9 years ago

took the vehicle out for a road test on the highway and it was running better and not backfiring when pulling a hill , still seems like the power is still down a bit but better went about 5 miles does the problem get worse as the engine runs . disconnected the egr vacumn hose like you said didnt seem to make much difference . what would happen if i just took off the hose to the engine for 3 or 4 days ?

Ford Mechanic: POWERSTROKE, Ford Mechanic replied 9 years ago
Did you slowly bring the truck up to 1200 rpm then disconnect the hose and see if the misfire goes away? If you disconnect the vacuum hose it will set a check engine light for egr low flow. One other thing to check if the egr ports are not plugged would be to check the valve springs for #6 to see if they are broken.
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Customer reply replied 9 years ago


thanks i will test drive it again and check the egr valve again but the engine wasnt missing when i tried to do the test i let the engine warm up before i did it . its snowing and cold here wont be able to pull off the valve cover as im working outdoors and have to work tomorrow

Ford Mechanic: POWERSTROKE, Ford Mechanic replied 9 years ago
Ok let me know. I will be here until we get the problem solved
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