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ZBrink

Struggles to Start When Cold, P0300 Code, Engine Running Smooth

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2000 5.3 is struggling to start in the am as if it's not getting fuel but once it starts it seems to be running perfectly fine. If I stop at a store, it fires right back up when I come out. Service Engine light stays on steady then flashes periodically. My basic scan tool is showing code P0300.  When I check out the section in the scan tool for emissions testing purposes, it reads "Evaporative system leak test failed" yet no codes are actually displaying for this.

 

Truck has new plugs and wires and a new crankshaft position sensor.

 

Common issues to resolve all of this? 

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Have you changed intake gaskets?cold,they are contracted,heat,they expand and fill the leak,in a.m,or cold motor,spray some carburetor cleaner at manifold gaskets,see if it changes r.p.m,and with the evap,it's a pending code,not a full,hard code yet,but probably coming soon,gas cap?oring not cracked,filler pipe where it seals,clean? just starter points

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1 hour ago, riverbanks said:

Have you changed intake gaskets?cold,they are contracted,heat,they expand and fill the leak,in a.m,or cold motor,spray some carburetor cleaner at manifold gaskets,see if it changes r.p.m,and with the evap,it's a pending code,not a full,hard code yet,but probably coming soon,gas cap?oring not cracked,filler pipe where it seals,clean? just starter points

Do you think the two may be related or a coincidence?

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If the purge valve on intake manifold can't close, problem,if it closes, coincidence,cold motor,pull some vacuum on purge valve,holding or not?

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So where are you at? monitors complete? problem not solved after work done?

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The truck would die after running for a few minutes then wouldn't crank back up. Mechanic replaced the crankshaft sensor. After that repair, this new issue began (of it cranking for too long when cold before start). It is now drive-able where before it was not.

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Ok,I'm not familiar with your scanner,or is it a code reader?is live data,a function?

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I had a p0300 I fought for a year. After replacing all the O2 sensors, the crank sensor, spark plugs & wires what ultimately fixed it was the fuel injectors need a professional cleaning. After I got the injectors cleaned the code has not returned. It has been several months now. This was on a 2002 5.3L Silverado.

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