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A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Mercury
Satisfied Customers: 6299
Experience:  ASE Master Certified. ASE Gasoline Engine Performance Certified,Ford Senior Master Technician
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Mercury Milan: My 2006 mercury milan is missing on cylinders

Customer Question

My 2006 mercury milan is missing on cylinders 45 and 6
Submitted: 1 year ago.
Category: Mercury
Expert:  A. Penland replied 1 year ago.
Hello and thanks for using JustAnswer.I will try my best to help you with your question.
What have you done to try to fix this problem?
Customer: replied 1 year ago.
I scanned with pocket scanner and got the code indicating the missing cylinders. I have cleaned battery terminals, un plugged each of the coil packs nearest the radiator independently with no change in idle. It of course threw the new codes for coils.
Expert:  A. Penland replied 1 year ago.
What original code did you get and what codes did you create when you unplugged the coils?
Customer: replied 1 year ago.
Original codes po300,po304,po305,po306 po457I don't remember which codes I got unplugging coil packsI cleaned the gas tank fill cap and don't get 457.( the fill cap light had been on)
Customer: replied 1 year ago.
After running the car a bit more (codes cleared) I now get po2195 and po171
Expert:  A. Penland replied 1 year ago.
Those two are lean condition codes for the back side of the engine near the firewall which is bank #1. This is usually caused by a vacuum leak, a bad injector (leaking or clogged), low fuel pressure or a not properly seated air filter box lid.
Is the engine still running rough?
Customer: replied 1 year ago.
Yes it is still running rough. The air filter box lid had been open when I first started working with this car.
Customer: replied 1 year ago.
I got this code after I close that up properly
Expert:  A. Penland replied 1 year ago.
Did you have the engine running with the air filter box open? Did you clear the codes before you started the engine with the air filter box closed?
Customer: replied 1 year ago.
I have cleared the code with the box close I cant just say if I have had the engine running or not when I cleared the code
Expert:  A. Penland replied 1 year ago.
A miss fire will cause lean codes also. I would inspect the spark plugs on the back cylinder head. Also the coils. You will have to remove the upper intake manifold to do this. heck the rubber boots on the coils that slip over the spark plugs. Check for oil leaking into the spark plug hole. Also, check the coil boot for burn marks or heat marks.
Customer: replied 1 year ago.
I removed and replaced all three coils and plugs on bank 1. it runs no better except one time I removed intake boot and it ran perfectly for a minute or two. now its back like it was.went and filed with gas 18 miles round trip engine light flashed briefly now get po 171,po 300,304,305,306
Expert:  A. Penland replied 1 year ago.
Bank 1, cylinder #1,2 and 3 are on the back cylinder head near the firewall. Bank 2, cylinders #4,5 and 6 are across the front cylinder head near the radiator. P0304,P0305 and P0306 are for cylinders 4, 5 and 6.
Customer: replied 1 year ago.
Ok I replaced the plugs and coils on cylinders by firewall. I replaced when you recommended to check back cylinders. Everything looked good except one boot came apart when I removed it.
Expert:  A. Penland replied 1 year ago.
I asked you to inspect them because of the lean condition code you have, P0171 and P2195.
Customer: replied 1 year ago.
What do you recommend at this point? Today I replaced 02 sensors on back side of engine and on exhaust pipe.
Expert:  A. Penland replied 1 year ago.
Why did you replace them? You had lean codes which the 02 sensors where telling the PCM. There were no codes that told us to replace the 02 sensors.
When you stated the coil boot came apart, did it just separate from the top of the coil, or did it actually come apart.
Customer: replied 1 year ago.
It came apart in pieces.
Expert:  A. Penland replied 1 year ago.
Ok. Inspect the front three. See if the coils are bad. If they do not break apart, then inspect the spark plugs.
Customer: replied 1 year ago.
Coils look ok. Spark plug on left side wet with oil.
Expert:  A. Penland replied 1 year ago.
That is caused by the valve cover gasket. Replace the valve cover gasket and the seals for the openings for the coils which is on the valve cover. Then clean the coils and plugs and retest for miss fires. If it still miss fires and gives you codes for those cylinders, then replace the plug and coils for the codes you receive only.
Customer: replied 1 year ago.
OK
Expert:  A. Penland replied 1 year ago.
The oil will cause the coil to short and not send spark to the plug. Water does the same thing.
Customer: replied 1 year ago.
I did the valve cover gasket. I put the plugs and coils that I had removed from bank 1 and put them in 4,5,and 6. Started and almost immediately got po 300,304,305,306. I ordered new plugs and coils for tomorrow... Not sure that will fix it.
Expert:  A. Penland replied 1 year ago.
Please keep me informed.
Customer: replied 1 year ago.
I just had my local shop guy check it with his scanner. He got the same codes I did. Which are 171 300 304 305 and 306 he also got a code 336. his first thought was mass air flow sensor or crank position sensor. after listening to it wrong he thought jumped timing chain
Customer: replied 1 year ago.
Sorry that should say after listening to it run he thought jumped timing chain
Expert:  A. Penland replied 1 year ago.
If he thinks it jumped time, then a manual compression test will verify this as the front cylinder head, cylinders 4-5-6 will be al lot lower than the back cylinder head cylinder 1-2-3. But there is only one timing chain for this engine which drives both camshafts.
The timing chain tensioner is closer to the rear cylinder head and the chain drives those cams first, then the front cylinder head. There is a chain that connects the exhaust and intake camshafts on each cylinder head.
Have him do a manual compression test before taking anything apart.
Customer: replied 1 year ago.
Compression is as follows
150,150,150 bank 1
145,145,150 bank 2
Expert:  A. Penland replied 1 year ago.
5 PSI difference is not that bad. Possible sticking valves in the valve guides, but I doubt the timing chain jumped. But I cannot hear the engine running like your mechanic can.
Customer: replied 1 year ago.
Do you think I should try crank position sensor?
Expert:  A. Penland replied 1 year ago.
That would make it miss on all the cylinders. not just 4-5-6.
Customer: replied 1 year ago.
What would be your next move?
Expert:  A. Penland replied 1 year ago.
Do a cylinder leakage test on 4-5-6 and see if they are leaking past the valves or the piston rings.
Since swapping the coils and replacing the plugs did not change it, then it is either fuel injectors or sticking valves.
Customer: replied 1 year ago.
Could it be a PCM driver or would we have seen extreme heat on the coils?
Expert:  A. Penland replied 1 year ago.
You would also get P0354 or similar codes like P0355 and P0356.
You can check the coil circuits with a NOID light. Unplug the coil and plug a NOID light in the harness connector and start the engine. See if you get a constant flash.
Customer: replied 1 year ago.
OK
Expert:  A. Penland replied 1 year ago.
Do the same to the fuel injectors if you can reach them.
Customer: replied 1 year ago.
I tested all the
Customer: replied 1 year ago.
Harness connectors for 4 5 & 6 and they give a dim flash possibly due to low idle speed.
Customer: replied 1 year ago.
Also tested injector 6 it was the only one I could reach and also got a dim flash. fuel pressure is that 70 psi
Expert:  A. Penland replied 1 year ago.
I just wonder if you are getting any fuel from the injectors into 4. 5 or 6.
Have you swapped injectors from one side to the other and cear the codes.
Customer: replied 1 year ago.
No I have not.
Customer: replied 1 year ago.
It stalls when I unplug harness to 4 5 and 6
Customer: replied 1 year ago.
Could this be caused by a voltage problem? the other day it was completely dead. today I tried it after it had sat for several days and it was fine however later this evening after leaving the key on the headlights were flashing. this does not have automatic headlights.
Expert:  A. Penland replied 1 year ago.
There is definitely some electrical issues if the headlights flash.