My truck was acting retarded a few days ago and started to flash this code,,brought it to my mechanic and it turned out to be a "harness wiring issue leading up to the pcm"..
Im posting this up because when i had this problem and i was googling it to get some info on how to fix it,people where saying to check spark plugs,fuel system,distributer etc...but no mention of checking the wire harness. ..this was my problem and i have gotin it fixed and maybe this thread can help someone else who has checked spark,fuel,distributer etc..and is still having this problem then check out your wiring harness wires...i dont know exactly which specific wires they where but once i get intouch with my mechanic again i will ask him and will update..i also had a p0336(crankshaft sensor replaced)..i had both of these codes on and my truck would sometomes randomly cut off while driving untill just a few days ago it cut off and did not start back up this time...
Not sure if this was the p0336 fault or the p0300s fault..anyways both issues have been resolved

 

Please let me know what harness he replaced and where he got it from. Part number.

I also have p0300 and checked everything. Comp test, Coil, plug wire, fp, injector, plugs..... #2 is still missing. I am running out of options.

 

Fo real.

 

I found an injector harness on amazon last night for 23 bucks. Itll be here in 3 days. Ill swap the harness and hope for the best. If that doesnt cure the miss, ill drop it off to the shop that inspects it.

I seen you can disable P0300 in HP Tuners, but I want the issue fixed. Its a pain right now because I use the remote start and it will shut the engine off when the code is thrown. Also if the code is outstanding, the remote start will not work. Cool feature but man it sucks when its a miss and the middle of January here in Buffalo

 

@ Westbank25

FYI, It's only helpful if you post up what type of vehicle you own. Year, make, model

 

My truck was a 2000 rcsb 4.3l 5speed manual..i called the mechanic and hes not being very helpful in telling me what wires exactly,he just said i had a bunch of wires leading up to the computer chewed up

 

" diagnostic check and replace crank sensor and damaged wire and harness to computer"

 

HA ok, thanks. I havent seen anyone replace the crank sensor for P0300, maybe I should look into checking it

 

No no i also had the crank sensor p0336 CEL code come on and needed to replace that as well because my truck wouldnt start,,thats besides the p300 code..

 

It does make sense since the crank sensor is used to tell the coils when to fire.