JM_1

have a 96 3500 wyhen sitting in netrual if u put the fuel to the floor the engine will sitt at about 2400 RPM and blow bluish smoke until you let off does same thing in first gear always once and a whikle in second wont do it under load or when towing if you gradually ease into the throttle under no load wont do it just if youi put it to the floor under a light load or no load under heavy load its fine doesnt blow smoke or anything also seems to be loosing power more an more any ideas truck has 335,000 miles fyuel filter has been changed.
is this something simple or is the injection pump going on it ?

kandgo

Unless your injector pump has had work done on it,you are probably reaching the top of your fueling and it is defueling,your tach could be reading wrong so as it looks like it is defueling to soon. Clean air filter? Pre filter screen dirty? Bad load of fuel? Drawing air somewhere? It does have the miles on it,could be a clogged injector,run some cleaner thru it. Goodluck Rick

signature600

Mine does the same thing, and only has 233,000mi. I think, and have been told by people more educated than me, that the timing has slipped. Try that.

kandgo

Forgot about that one,jm-1 the timming has been known to slip. Goodluck Rick