[rover1]

can any one help please i have a 2000 4runner when i tow my boat (1800lb approx ) i get a code 300 303 306 i checked with the obd 11 random misfire cyl #3 and #6 , i have changed the plugs swapped the coils changed the upstream o2 sencor , still have the light it flashes at first and then stays on . i fell nothing in the truck , any one have ideas please if i do not tow my boat no light , one thing i did do is i towed my boat in overdrive on light out of od light flashed , put it in od went out , it seems to be rpm related .

help please andrew

 

[bad954runner]

does the SES light come on and start blinking or anything?

 

[rover1]

ses (check engine light ) blincks at first then says on thats when i can get the codes , any ideas

thanks

 

[chronoti]

this might sound crazy but it sould a little todo with your tranny. i guess it might be shifting a little hard or something doesnt line up or realse right cause a large enough shock or vibration to set off the knock sensors. since the 2 cylinders near the tranny are setting this off. have you changed your tranny fluid?

 

[rover1]

this only happens when i am on the highway at a steady speed 55mph out of od and the highway is flat , yes i have changed the tray fluid no bad smells or wrong colour , like i was saying its only happens when i am towing , on the highway out off od rpm about 2800/2900 , when i put it in to od the light stops blinking and says off , its rpm related i think i feel nothing in the truck .