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Q: rough start, high idle on start, missfiring and bogging out

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hi, my truck has been having some rough starts lately and its practically brand new, also on the initial start of the vehicle on most occasions in idles into the 2k rpm range then settles down after about 3 minutes. also my truck has been bogging out and misfiring and almost wont downshift when I need the power to get up a hill or something. I don't know if I have a vacuum leak or what. please help.

My car has 15000 miles.
My car has an automatic transmission.

A: If you have a check engine light on then ha...

If you have a check engine light on then have it tested to see what fault codes are present. You should still be under warranty and the dealer will fix it for free if it’s a failed part. If it is fuel related then they will charge you. If you all of a sudden started to have this issue, then think of when it started. Did you just get fuel? You may have just gotten a lot of water in your fuel and this will cause the problems you are having. Try to buy a product called ’dry gas’ from your parts store and go to a different fuel station. Pour the ’dry gas’ into the tank, then fill the tank with fresh fuel, and this should help disperse any water you may have got in the tank. If it starts running better then keep using the dry gas after the tank is down to a half of tank and refill it again. You should get rid of the bad fuel in a couple of fill ups. If it runs so bad you cannot drive it then you will have to get the bad fuel removed and fresh fuel put in. If the problem persists and you are not under warranty, then you should contact a qualified independent technician, such as one from YourMechanic, to diagnose your rough running issue.

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