Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
obd po300 on scanner misfire data shows on cold start up all over but after warm up when at idle cyl 2 & 7 when in motion cyl6 is the one misfiring but theres not one cyl thst doesnt misfire plz help
what are the misfire counts for each cylinder?
how often does each cylinder misfire? 1-3 times per misfire cycle before misfire counts reset on scanner?
let me know
Ok with it being that low of counts well need to check several things
1 fuel trims... if you have graphing capabilities well need to look at o2 sensor voltage readings for bank 1 & 2 upstream and down stream.
2 maf and map sensor readings at idle, 1500, 2500 rpm
3 condition of spark plugs (when was the last time they were replaced ? What do they look like (black soot covered to Tanish white ) pics would be ideal...
4 fuel pressure at idle and key on engine off and does it bleed down fast or stays at that pressure for a while?
5 condition of throttle body is it dirty around throttle plate (if yes clean it with throttle body cleaner)
6 condition of fuel did this happen after a fill up? Bad gas is possible rare but possible
7 air filter is it clean or needs replaced?
Has a rats nest in filter housing etc
Topic Author
