My truck randomly misfires and idles very bad and sometimes the check engine light turns on. I have changed the coil,cleaned fuel injectors,I even had the computer changed by the dealer.This has been happening for about 2 1/2 years now. I discovered that if I accelerate at idle up to 3500 rpm's that this will clear the sputtering and my truck will idle normal.Now I am getting a check engine light for a vacume leak in my fuel system. Can this be related? Could the vacume leak have been causing this all this time,but just now getting the check engine light for the leak? My truck is 2004. No one can tell me why only cylindar 2 is mifiring.
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2004 Dodge Ram 1500
Question: What could the cause of a cylindar 2 misfire?
Answer #1patrick mannion from Greg Solow's Engine Room, February 21, 2012, 21:59Master
Even though the injectors were cleaned I have seen them fail! Start with the basics, check compression and do a cylinder leakage test to ensure the engine is sound. Make sure there are no vacuum leaks at #2 intake manifold area.
With a professional grade scan tool you can see misfire count, fuel trim figures to see other information to pin point the problem. With the engine running wiggle electrical connections in the engine compartment to see if the engine idle changes. Maybe try changing #2 injector to another cylinder see if the misfire follows the injector. I assume the spark plugs were changed. To check for vacuum leaks Many automotive repair shops have a machine that generates an inert non flammable low pressure smoke that looks similar to cigar smoke. The intake manifold is sealed off, and smoke is put into the engines intake manifold. The smoke then fills the engines crankcase and if there are any vacuum leaks from gaskets, hoses, or housing smoke emits from the source of the leak. Some mechanics will use propane or aerosol carburetor cleaner, with the engine running they will spray the cleaner or propane around the intake manifold and vacuum hoses. A leak will cause a "lean mixture" condition, when the flammable fuel (carburetor cleaner or propane) comes in contact with the source of the vacuum leak the engine idle speed will raise as the engine has received "fuel". this method of finding a vacuum leak works but is not recommended as it can easily cause a fire.If your truck is at a repair shop and they are stumped, there is a professional service called Identafix. http://www.identifix.com/info/about_us.htm They only deal with professional repair shops. They are in the Minnesota 651-633-8007 begin_of_the_skype_highlighting 651-633-8007 end_of_the_skype_highlighting. Your auto repair shop do all their diagnosis tests, and discuss your problem with a team of professional technicians great service cheap and very bright people. If the repair shop that are repairing your car are stumped this is a great service. This company only deal with automotive repair shops and don't answer questions for the general public but are an amazing knowledge base.
ReplyZitroV, February 22, 2012, 06:22Rookie
Thanks a bunch. I actua lly will be dropping off my truck morrow mormning. If there is a leak at the cylandar,will this read as an error code when a diagnostic check is done? I'm hoping the mechanic will find dthis with a gesneral leak search as apposed to looking directly at cylandar 2 .There is no misfire error at this time,just a vacume leak error.