A misfire under load can be a spark plug, or carbon tracked boot. If it is a continuous misfire on a given cylinder, it could be a coil, or primary trigger, possibly even a fuel injector or injector control. I am assuming that you have determined too much air by a lean code(s), like P0171/174. If you are getting a lean condition on both banks, it most often is the result of a central vacuum leak after the mass airflow sensor. A common location for the vacuum leak is the boot that is between the plastic intake, and the aluminum throttle housing. This leak is most often at the lower portion of that boot, and may be heard, but not seen. Another means of confirming that it is in that area, is by inducing a propellant in that area, I use a propane wand because it is safer. Adding carb cleaner or equivalent to that area on a hot engine can result in it flashing. Water will also work, you should notice a difference in the smoothness of running, or a drop in the engine speed if it is idling higher than normal. The lean condition can also contribute to some light misfiring.
If it had a P0741, the only logical approach to that after removing the transmission, is to replace all the seals in the TCC hydraulic circuit, as well as the solenoid, and the converter itself. There is no certain method of locating the internal leak, and you only want to do the job once.
Wednesday, June 22nd, 2011 AT 4:55 AM