Hi I am new to the forum as I have just purchased a 1990 Ram 1500 with a 318. It has done 225,000 kms but misfires when cold like it is running on 7 cylinders, but runs more smoothly when it warms up.....there is also a slight tap when it first starts up...but i guess it is expected with the kms it has done. The previous owner states that the cold misfire and rough running could be the injectors or the distributor cap? I am only going to use the truck locally with runs to the landfill etc, but i want her running properly and really like the look of the truck. The body is pretty solid for its age.....Any pointers would be really appreciated

 

you should start by just checking the spark plugs. they tell you whats going on in your engine. then you should check you cap, rotor and wires.

 

Doesn't sound like injectors since they provide fuel to all cylinders in a TBI system and therefore don't cause a misfire condition. It is probably electrical but I would flush the oil system to try to stop the tapping. A sticking lifter will cause a tap especially when cold and could be causing a misfire condition until it loosens up with the heat of the engine.

 

Thank you so much for the pointers.......I will check it out and let you know how I get on.
Eddie