p0300 trouble need advice please
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Joined: Feb 2013
Posts: 12
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From: chicago,il
p0300 trouble need advice please so i had my long tubes put on than i extended my 02 sensor wires the upstream pre cats i installed them all went well for a while, car had loads of power than all of a sudden it start to missfire pretty bad, idle ranges from 900 rpm to 5-600 rpm and while driving the car stutters and bogs out of power runs very heavy, the check engine light flashes occasionally i know its a missfire but i do not know where to begin i have p0300 code coming up random missfire my dumb freind decided to clear all the codes so know i cant even go back to them there were 2 others for the down stream 02's i beleive, any advice?
Also, if the headers were new and coated they have been known to mess up the O2s. Do a search on here I'm sure there is a way to pull them be able to tell if they got messed up by the header coating.
