Doc99SS

iTrader: (2)

ATAP is showing multiple misfires on all cylinders.

The engine starts just fine, but seems to run a bit rough, but so far, I have attributed that to the large duration cam. The cam may be just lopy. Can a large duration cam cause misfires? I am a bit lost in tuning this cam. I do not know what to expect.

rel3rd

iTrader: (43)

Absolutely. My cam is just a baby at 226/226 and it set misfire codes. Also the torque converter would not lock due to misfires. Once sensitivity to misfire was changed, no more codes, and converter worked as meant to.

98FreakZ

iTrader: (1)

if your knock sensors are still turned on in the computer a large cam with big duration can give false misfires... found out the long way

Doc99SS

iTrader: (2)

Once sensitivity to misfire was changed, no more codes, ....

How do you changed the sensitivity? Should I desensitize the knock sensor? I think that if the knock sensor picks up knock then the PCM will pull out timing. So this should not be the right direction to go.

2xLS1

iTrader: (25)

Knock sensors have nothing to do with misfire detection. It is all done with the crank position sensor and the reluctor wheel on the crank. You will never get accurate misfire detection with a cam that big. Set all the misfire tables to their max values. Misfire detection in programmed in stock engine/cals to save the life of cats when real misfires occur.

Randy WS6

iTrader: (69)

if you have a tuning tool, just turn it off, code PO300 multi misfire.

Doc99SS

iTrader: (2)

Thank you for the advise. I have LS1Edit. What are the step to turn off the misfire code?

I selected Engine Dianostics; then selected teast = P0300; then toggled off "does Error Set SES"; then toggle off Error mode, Type X = turned off.

Will this do it?