I felt mine misfire. It's like riding a bucking bronco. :-) At first I
thought the torque converter was on steroids because it would only occur
during overdrive at minimum speed, like 45-50 mph going up a freeway
entrance ramp.

It was a TSB item over a year ago.. fixed now.... hmmm... on second
thought I will have the plugs changed at 30,000 miles. I had carbon
build-up from short drives to work in cold weather.


0900303 - 4.0L MULTIPLE CYLINDER MISFIRE
Date: 08/01/03
Model Year(s): 1999-2004
Description: NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A
4.0L ENGINE. This bulletin involves inspection of all engine exhaust
valves and a decarbonizing procedure if necessary.

Details: The customer may experience an incident of engine misfire
during certain vehicle operating conditions. The misfire may occur when
the vehicle is operated between 50 - 70 MPH and under light loading
conditions, e.g. slight uphill road grades. This condition may occur at
all ambient conditions, but is more noticeable when ambient conditions
are less than 0 C (32 F).

If the vehicle is equipped with On-Board Diagnostic (OBD), a MIL
illumination may also have occurred due to Diagnostic Trouble Code (DTC)
P0300 - Multiple Cylinder Misfire. Various single cylinder misfire DTC’s
may also be present. If the frequency of misfire is high the Powertrain
Control Module (PCM) may place the engine in “Limp-In” mode.
The misfire condition may be caused by one or more engine exhaust valves
that are slow to close. Late closure of an exhaust valve may be the
result of no valve rotation and associated build up of carbon on the
exhaust valve stem.
This condition may occur when the engine is not allowed to run at engine
RPM’s that are greater than 3,200 RPM. At 3,200 RPM or higher the engine
exhaust valves will rotate if not impeded by high carbon deposits. Low
engine RPM’s and high carbon deposits are associated with short trip
driving where the vehicle engine is not allowed to fully warm to normal
engine operating temperatures. Cold ambient temperatures will increase
engine warm-up time and add to the opportunity of carbon deposit
build-up on the stem of the engine exhaust valve.



"Matt Macchiarolo" > wrote in message
...
> Bill, have you ever even felt a 6-cyl engine misfire? If you had, you
> would know that mine is not.
>