I have a 99 Honda Accord. It has a miss/rough idle when its parked for more than 4hrs maybe, but specially in the mornings. It's only at the first start, after that it runs normal. I have changed spark plugs, wires, fuel filter, fuel pump, and nothing has change. I took the car to scan it and it shows no sensor is bad, the person said that according to his experience it can be something in the fuel system because scanner is not reading any problem. Only thing I need to do is clean the injectors. Mechanic told me to put in the tank a bottle of fuel injector cleaner but I am wondering if its better to let a professional clean it. Or if there is anything else that can be the problem other than the fuel injectors. Please need help as I have spent a lot of money already and I am very frustrated at this point. Thank you in advance

  • Are you getting any fault codes out of the system at all? – Lynn Crumbling Nov 17 '14 at 21:57
  • nothing, it shows like if everything is working properly – JXG Nov 17 '14 at 22:36
  • When starting again after more than 4 hours, try leaving the ignition into On position for about a minute and see if that helps the startup. If it does, then yes, it's likely a fuel-related issue. Leaving the ignition in the On position starts the fuel pump via a relay. Injector cleaning alone might not fix the issue - it could be your fuel pump as well. Have a fuel pressure test done perhaps. – gAMBOOKa Jun 20 '15 at 13:22
  • @gAMBOOKa - You need to post this as an answer so we can have an answer for it. While I don't know if it's thee issue, it could definitely be an answer. – Pᴀᴜʟsᴛᴇʀ2 Dec 15 '15 at 0:21
  • It is essential to know which engine; 4 cylinder or V6. The V6 of this era has a fuel vapor lock problem that has no known fix. The 4 should be repairable with proper testing. – Fred Wilson Dec 15 '15 at 6:21