URGENT !!HELP!!!! my silverado 5.3l 2003 code P0300

marc

WhiteSilvy
May 16, 2013
5,303
123
0
32
canada
okay today got in my truck it was -22C or -8F truck started fine let it warm up for a good 20 mins while i got ready for work....took off slowly as i can for work after 15 mins of driving i had to get on the hwy sorta cut in front of someone so i stepped on it pretty good.

so i went up to 110km/h or 70mph and my check engine light stated flashing threw my OBD2 code checker on there and scanned it while getting off the hwy pulled over shut it off started it back up and started flashing once i started going.....it threw the code P0300 that is after 2 days ago throwing P0131 ...

any one know where to start... is it ok to drive ? since i am looking at a new truck this afternoon....does my truck just hate the cold ?

any help is appreciated


:pissed:
 
Make sure your spark plug wires are connected securely and not broken. The evap code may be nothing or the vent valve may have frozen stuck. Try to get it somewhere warm and disconnect the battery and see if that helps.
 
only thing i know is fords at uhaul sometimes through lean bank 1 and faulty o2/cat bank 1/2 all the time and they say to use to just reset it so i dunno.
 
worst case is injectors, start with simple wire or plug as suggested.

The evap can end up being the entire canister at times, or something simple
 
i really need to know if i can drive it or i have to cancel with the guy with the lbz ....
 
I've had this p0300 code before on my 99...right after seafoaming. plugs were fouled.

that's not a bad idea to do, ill check into it and since ive owned it i haven't changed the plugs :facepalm: so will get those changes, sea-foam, run some injector cleaner in the next tank and hopefully all goes away :pray:
 
I've had both codes for a while. No issues driving it so long as you don't notice a change in how it drives/behaves. 0449 can be the small evap can behind the tank that is $20 to replace.

0300 can be a number of things. Bad cats can also cause it to come up from what I've been told.
 
just a misfire, flashing can mean you had a cyliner not firing at all for more than a a certain number of consecutive pulses. if it is still drivable at all you probably just fouled a plug or ran into a bad bit of fuel.
 
just a misfire, flashing can mean you had a cyliner not firing at all for more than a a certain number of consecutive pulses. if it is still drivable at all you probably just fouled a plug or ran into a bad bit of fuel.

hopefully thats it .... i will get spark plug and sea-foam and injector cleaner on my way home from work.... it idles really rough and low rpm's