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Q: engine misfiring? on 2005 Honda Civic

Hi I have a 05 honda civic LX 5 speed with 74000 miles. Has a little bit of a rough idle, the check engine light is on and blinks when sitting in idle. When driving it stops blinking and just stays on with out the blink. OK, so got a dianostic and it says it is misfiring in all 4 cylinders. We changed spark plugs, didn't help. Then we noticed that when we unplugged the first coil pack closest to passenger side while the car is running it didn't disturb the the idle or the way the car was running. So we switched the coil packs around to see if the passenger side would start working or to see if coil pack went bad, still made no improvement. So we thought it was an injector, replace that and still same mild rough idle with check engine light. By the way the acceleration seems fine with no hesitation and same goes for starting the car, both are fine. Just in idle for the most part is the problem. Ok so what do you think I should do next or what do you think the problem is? Thanks!
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Can you post all the trouble codes that you are getting? Be careful to not include any codes that were created by unplugging coil or injector while it was running.
Also, check for vacuum leaks in the intake system, especially the intake manifold, and check cylinder compression in all cylinders.
Here is some info regarding the diagnostic codes you received:
I don't remember the specific codes autozone told me, so I'll take a trip over there and tell you by friday. Thank you all for your help!
The Codes are P0300,P0301,P0302,P0303,P0304 Now we are thinking the problem is that the Idle Air Temperature (IAT)sensor went bad. What do you think? Thanks again!
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