Can you help?? I live in the UK and have a 2004 1500 SLT 5.7 Hemi 4x2 Regular Cab, it is a great truck but has developed a problem in the last few weeks that the English dealers / specialists are stuggling to fix. The engine developed a slight mis-fire and the engine light came up on the dash, when pluged into the computer the code suggested a faulty injector (no. 4) was causing it, this was replaced and sorted it for about 30 mins then the mis-fire came back!!. The computer now says it is a multiple mis-fire and is running rich with the fault code 300 but does not specify where it is coming from, the injectors have all been checked as have the plugs and leads, could it be a faulty ECU?? The mis-fire is intermitent, but is always there when starting the engine whether cold or hot, and causes a hesitation when trying to start, the mis-fire which can come on when cruising down the motorway is cleared if you give it some revs?? any ideas?? please??

 

Sounds like debris in the fuel. Try getting a system flush and use a different type of gasoline.

 

get the fuel pump checked to see if it's putting out the proper pressure. that would be the first thing I would think of, second would be to change out the fuel filter.

 

If that doesn't work check your spark plug wire's ,one could be bad or loose.

 

Thanx for your replys, it can't be the fuel system as the truck has an LPG conversion and the problem happens when running on both of the fuels, the plug leads have been checked!! may just replace them to be sure!

 

Mis-fire is sorted.. It was a faulty spark plug. Apparantly the Hemi 5.7 is known for spark plug problems leading to a intermitent mis-fire. When driving it doesn't feel like a plug problem as under load it clears itself!!! Hope this helps other Hemi owners....