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

When's the last time you tuned the thing up?

Also, in the future don't freak the fuck out, chill the fuck out, read all the suggestions you get and act on them.


Also, don't lock your keys in the fucking truck while it's running :lol: How did you manage that? Does your truck let you lock the doors with the lock switch while your key's in the ignition and the doors open? Mine doesn't. HAVE to use the key fob.
 
Oktain said:
When's the last time you tuned the thing up?

Also, in the future don't freak the fuck out, chill the fuck out, read all the suggestions you get and act on them.


Also, don't lock your keys in the fucking truck while it's running :lol: How did you manage that? Does your truck let you lock the doors with the lock switch while your key's in the ignition and the doors open? Mine doesn't. HAVE to use the key fob.
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i think maybe i pressed the button with my elbow or something :shrug: and i guess mine is different because it was definitely locked

i changed all the fluids and air filter and stuff never changed the belt or spark plugs but yeah that's about all i hadn't changed

but did just do wires and plugs

and i freaked out because my check engine light was flashing and i have bad experience with flashing lights :secret:
 
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okay so went and did the whole check for leaks in intake gasket with brake clean ....but since its misfiring i cant tell if the idle changes or not .... should i just change it Saturday ? and see if it fixes it ?

any tips ?
 
Oh you'll know if it has a leak. It won't just "change" the idle, it'll idle way up for a second and go back down
 
Huck said:
Oh you'll know if it has a leak. It won't just "change" the idle, it'll idle way up for a second and go back down
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oh well it didnt do that and i sprayed the shit out of it

i will go try it again with a bit more light to make sure i get it in all the spots

you think it might just be my 02 sensor ?
 
Unless somebody knows something I don't, I'd say your intake gaskets are fine. LS intake gaskets are awesome, I'd HIGHLY doubt they're bad (granted, there's an exception to every rule), but they're reusable even so it'd be some REALLY shitty luck to have them go bad. I put knock sensors in my truck at ~155k miles and my gaskets were still perfect so I reused them.

It seems like you're chasing your tail and I know how much of a PITA it is to track/diagnose electrical yourself and it's hard to help over the internet. It may ultimately be cheaper for you to take it to a shop and get it diagnosed. If it's a stand-up, trustworthy shop, let them diagnose and then if it's gonna be expensive for them to do the work, just tell them you wanna try it yourself first. They'll charge you a diagnostic fee, but it'll be cheaper than guessing and throwing parts at it. IDK if he's a whole shop or just a tire shop but take it to Brandons
 
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Huck said:
Unless somebody knows something I don't, I'd say your intake gaskets are fine. LS intake gaskets are awesome, I'd HIGHLY doubt they're bad (granted, there's an exception to every rule), but they're reusable even so it'd be some REALLY shitty luck to have them go bad. I put knock sensors in my truck at ~155k miles and my gaskets were still perfect so I reused them.

It seems like you're chasing your tail and I know how much of a PITA it is to track/diagnose electrical yourself and it's hard to help over the internet. It may ultimately be cheaper for you to take it to a shop and get it diagnosed. If it's a stand-up, trustworthy shop, let them diagnose and then if it's gonna be expensive for them to do the work, just tell them you wanna try it yourself first. They'll charge you a diagnostic fee, but it'll be cheaper than guessing and throwing parts at it. IDK if he's a whole shop or just a tire shop but take it to Brandons
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yeah good plan, ill check gasket one more time just to be sure maybe check the wires going too my 02 sensors ... i did drive through a pile of snow a while back never know might have ripped off the wire or something :shrug:

and brandons shop is a shop not just tires he does everything so ill take it there pretty sure he will take care of me
 
Yeah, honestly that's probably the best idea. Just check everything you can, wires/connectors/ect that's free, and then take it to Brandon's. I know doing it yourself is cheaper and trust me, I'm the guy that cusses and despises and hates going to shops. I take pride in doing everything I can myself but there are times when it's the best way. Especially since there are so many sensors/connectors/relays/etc in these trucks. Electrical gremlins SUCCKKKKKKK and are IMPOSSIBLE to find sometimes without the proper scan tools. The cold really fucked something in your truck and I'd bet it's electrical so you'll keep chasing for months
 
Huck said:
Yeah, honestly that's probably the best idea. Just check everything you can, wires/connectors/ect that's free, and then take it to Brandon's. I know doing it yourself is cheaper and trust me, I'm the guy that cusses and despises and hates going to shops. I take pride in doing everything I can myself but there are times when it's the best way. Especially since there are so many sensors/connectors/relays/etc in these trucks. Electrical gremlins SUCCKKKKKKK and are IMPOSSIBLE to find sometimes without the proper scan tools. The cold really fucked something in your truck and I'd bet it's electrical so you'll keep chasing for months
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yeah might first take it too napa tomorrow its 2 mins from work have them scan it and maybe pin point the 02 sensor or other problem. if they cant find it its going to brandon
 
well they didn't scan it cause they don't do that anymore ... so i don't know :shrug:... i bought an o2 sensor it was 90 bucks.... but went to a shop and they said your o2 sensor wont be able to make my truck misfire... or run like shit ...is this true ?

also i bought one o2 sensor ...what one is my best bet too replace first i have all of Saturday and might be able to work on it in a shop
 
Who "doesn't do it anymore"? Any reputable place should. And an o2 can definitely make you're truck run like shit, they monitor the gasses as they pass from the front sensors to the rear and make constant adjustments thru the computer. They can really fuck up your air fuel ratio if they're going bad, I had a couple go bad on my truck and it ran like dog shit. It sounds like that shop doesn't know their shit

Sent from TapaTwat
 
Huck said:
Who "doesn't do it anymore"? Any reputable place should. And an o2 can definitely make you're truck run like shit, they monitor the gasses as they pass from the front sensors to the rear and make constant adjustments thru the computer. They can really fuck up your air fuel ratio if they're going bad, I had a couple go bad on my truck and it ran like dog shit. It sounds like that shop doesn't know their shit

Sent from TapaTwat
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napa the parts store used to scan codes and stuff to see what part you needed, but they have stopped doing that


and okay thanks, and the guy said something about 20 years of experience...

do you know what 02 sensor to start at if bank 1 is running lean ?
 
marc said:
well they didn't scan it cause they don't do that anymore ... so i don't know :shrug:... i bought an o2 sensor it was 90 bucks.... but went to a shop and they said your o2 sensor wont be able to make my truck misfire... or run like shit ...is this true ?

also i bought one o2 sensor ...what one is my best bet too replace first i have all of Saturday and might be able to work on it in a shop
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god damn, who the fuck said this...I in fact had one go out, and it was in fact missing, and in fact, once I replaced it, it went away...
 
Jared said:
god damn, who the fuck said this...I in fact had one go out, and it was in fact missing, and in fact, once I replaced it, it went away...
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lol i should give welsh his company # to troll :rofl:

but yeah i will change them one at a time tomorrow hopefully it fixes it, cause dam my truck isn't happy right now.... thanks for the info :shake:


the bad part is i have a date tonight and now i am going to look like a fgt driving my moms hyudai tucson :faceplam:
 
Sorry, was at work and couldn't respond any more. But IIRC, bank 1 is driver's side. Start the the driver's downstream (the one after the cat), if that doesn't work then do the upstream, then do the same on the pass side if needed
 
DirtyRed said:
Haven't read all post, have u checked fuel pressure? Low FP could cause multi-misfire.
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don't know how to check that ... but wouldn't it run completely lean and make all misfire ? we read what the 02 seonsors where reading and bank #2 was at consistent 550-600 and bank #1 was at 200-450 going all crazy

but dropping of truck at shop tomorrow
 
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