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MASTER TECH, Honda Service Technician
Category: Honda
Satisfied Customers: 5716
Experience:  28 years of Honda training and a master Honda tech
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car runs fine when cold, misses when warms up (closed loop),

Resolved Question:

car runs fine when cold, misses when warms up (closed loop), engine light does come on and blink, code scan just says missfire on cyld. 1 and 4, i know that a problem in closed loop usualy means a faulity censor but the computer is picking up the misfire but not the censor.
Submitted: 7 years ago via
Category: Honda
Expert:  MASTER TECH replied 7 years ago.
HiCustomer Thank you for asking your question on JustAnswer. The other Experts and I are working on your answer. By the way, it would help us to know:
-What year is your Honda?
-What model is your Honda?
-How many miles are on your Honda?
-What type of engine is in your Honda?
-What have you already tried?

Thank you again for trusting us with your problem. Please reply as soon as possible so that we can finish answering your question.
Customer: replied 7 years ago.
2007 civic w/ 1.8L, miliage is approx 37,500. so far inj cleaner is really all i have tried
Expert:  MASTER TECH replied 7 years ago.

have you inspected the spark plugs yet ? also look for signs of rodent damage. they like to chew wires and nest under engine covers where it's warm


are you able to unplug the affected cylinder and will it make a difference ?

Customer: replied 7 years ago.

plugs looked ok, smelt like gas, the threads a little moist but not the end of the plug it self, computer says misfire is 1 and 4, but all 4 plugs look the same. i thought the inj cleaner w/ cyld lube caused this

Expert:  MASTER TECH replied 7 years ago.

ok switch the coils around put the #1 into # XXXXX and see if it changes cylinders. you could have a coil that failed but i have not see 2 coils fail at once. at least we can isolate the problem

please advise

Customer: replied 7 years ago.
my first idea was faulty coils but as i thought about it i couldnt figure out why the coil would work fine and wait until engine warms up and is in closed loop before it starts mising
Expert:  MASTER TECH replied 7 years ago.

resistance plays a big part. thats why swapping the coils around we can see if it affects a different cylinder.

its a very easy step to take and it will lead us into the correct direction.

Customer: replied 7 years ago.
i dont have a scan tool at home and when it starts missing it wont hardly pull it self, i know that swaping them is easy i just dont have any way to see if the computer registers a different cyl. and also i did add dielectric grease to all to make sure the sockets hadnt became too dry
Expert:  MASTER TECH replied 7 years ago.
so we know it is not fuel related since the plugs have fuel on them so we have a combustion problem IE (coil,low compression or something mechanical)
Expert:  MASTER TECH replied 7 years ago.

thats why i was suggesting while it's running unplug the coil and see if if changes. if it does then the coil is firing and we can move to the next step.their is a process we need to follow.

you wont need the scan tool for these simple test.

Customer: replied 7 years ago.

ok, i will let it run until it mises this will take a few min, i will get back to you as soon as i know something

Expert:  MASTER TECH replied 7 years ago.

very well i will be here


Customer: replied 7 years ago.
i have let the car run now for approx 35 min and drove around the block about 3 times, so far no miss or engine light, could just unpluging and pluging the coils as well as adding the dilectric grease have fixed it, if it starts doing this again where is the first place you would start looking, yesterday i didnt notice the miss until the light came on and then it wouldnt hardly pull it self it mised so bad, they seemed to happen at the same time or at least when the computer noiticed the mis i didnt what ever cominsation it made, made it worse. thank you for your time
Expert:  MASTER TECH replied 7 years ago.


we see a lot of pin fit problems and yes some time just unpluging and plugging back in makes a new contact on the pin fit.


Expert:  MASTER TECH replied 7 years ago.

please dont forget to leave feed back after the accept.


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