Hi,

I was having a trip in bay area last week. After I filling up the tank with gas from Chevron and checked the coolant level, I started the car, the CEL came up. I drove back to LA and checked the code P0301, P0300. Then the shop asked me to change the spark plugs and ignition coils. The engine light didn't come on for the first 70 miles. Then it came up again and I checked it again. P0301, P0302,P0300,P0304, and a pending code P1399. I tried to change the TDS sensor. But now, the CEL comes back. Is it due to bad gas since I got that code after filling up the tank. or I need to change all 4 fuel injectors?

Thanks for all your help

Patrick

 

If the you are getting the misfire code and you have gone though more than one tank of gas and you have replaced the plugs and then the coil packs, then the next step is to replace the injectors.

 

i had the same problem and now and then the CEL would go off and bakc on. im about to change my injectors, if that doesnt work, ive heard it could be a bent valve?

 

My CEL have been staying on. Never go off.
I don't think I would have a bent valve though.... since the light suddenly came on after gas

 

And do you think I need to run though one tank of gas? I filled up my tank when there was half tank of gas left......

 

Clear the CEL by resetting the ECU...run through a fresh tank of gas and see if the CEL returns. If it does, then time to take next steps.

To check for a bent valve, do a compression test or a leak down test.

Otherwise, new injectors are probably the fix.

 

I've had similar problem and after going through a couple set of sparkplugs and two new injectors, check engine light didn't go away. It would turn off for a few days after installing new sparkplugs and injectors but then came back on. Turns out that the injector plugs were the problem. I took the contact taps inside of each injector plug out and bent them up to ensure that they make good contact when plugged into the injectors. I've been driving for almost half a year and no check engine light. Try doing that before buying new injectors. It just doesn't make sense that all four injectors are not working right.

 

i have the same problems, changed coils and spark plugs and it helped nothing. injectors are this weekend!

 

I took it to the dealership and they said I need valve adjustment and they will help me to look into the spark plug. Hope that would work

 

Just a heads up, newer hondas are very sensitive to misfires...there are a lot of things that can cause misfires. Please take your car to a reliable Honda experienced mechanic before you just replace coils, injectors and anything else related to fuel or ignition. Changing out these things can be costly and your chances of fixing the issues by just throwing parts at it is very slim. When Honda coils go out...they go out.
The main causes for misfires in newer Hondas are:
1) Bad fuel - old or water in it
2) Bad fuel - particles in it that clogs and causes low fuel pressure at higher RPM's
3) Valves being out of adjustment
4) Bent valve(s) - (loss of compression)
5) Possible software update (mostly in accords and Odysseys - some software versions released by Honda were too sensitive and later revised)

Now of course there are many other obvious things like a bad coil, short in wiring to coils or injectors etc..that can cause misfires but 1 of the 5 above is going to be the cause way more often. Any mechanic that just tells you to replace all coils and spark plugs shouldnt be charging money to look at cars or they should go back to working on domestics.

If you have over 30-40k miles on your car and have not gotten a valve adjust done...get it done!