813lexus

car starts up fine cold then starts missfiring after 15 minutes of driving and then after missfiring wont start let it sit for 15 to 30 mins starts up and drives for a couple of mins and the missfiring starts again and then wont start only codes are p1300 and po300 some times. replace inghter checked fuel pressure replaced, crank sensor, checked sparked the ecu was replaced by previous ower 2 years ago the car has 105k does anyone think bad ecu again? I have talked to some lexus mechanics I know and they dont have a clue please help I have also checked main relay and all grounds

GEORGE_JET

Here is a copy from the factory manual, it shows how to troubleshoot the P1300 code, I would recomend following it. Let us know if you have any questions.

llcoolpass

the way that some people check for spark is actually very dangerous to the ECU

how did you check the spark condition?

llcoolpass

and.. how did you miss this link when you googled your codes and searched this site before starting up a post on here?

http://en.allexperts.com/q/Toyota-Re...-misfiring.htm

and this

http://www.obd-codes.com/p0300

Dave457

Hi! Check the EFI relay, could use a new one.