HELP!!P0174CODE

99N/Afuturebeast

New Member
Sep 4, 2020
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28
kentucky
1999 mustang gt has ported and polished pi heads and ce262 cams, shortys and H pipe. I just bought the car and it had a missfire, rough idle and p0174 code which i believe is system too lean bank two. Replaced plugs, tps, iac, and got rid of the missfire code however it still has a missfire below 2000 rpm and a rough idle stalling occasionally. I have checked all vaccum lines including the ones going into the fender well, replaced plugs, maf looks to be spotless so i didn't clean it. There is an exhaust leak on the driver side header to H pipe flange that i am going to have to get fixed but i don't believe that to be my troubles if so i would think it would show a code for bank 1.The cops that are on it now are brand new although idk the brand they're red which made me think msd but they zero identufication on them. Could it be an injector or a COP, also thinking of replacing all injector and cop connectors incase that's my trouble there are a few clips broken. Any help would be appreciated.
 
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99N/Afuturebeast

New Member
Sep 4, 2020
11
0
1
28
kentucky
I will try o2s this weekend and see what happens im not sure what brand they are the previous owner replaced them and i believed him only because they have brand bew pig tails on them and the sensors them selves appear to be brand new.
 

Shuttleman83

Active Member
Jun 30, 2019
100
9
28
USA
Misfire code - try unplugging each injector and see if the engine starts sputtering worse. Also, cops are a possiblity. If the o2's are bosch brand, junk them.
 

99N/Afuturebeast

New Member
Sep 4, 2020
11
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1
28
kentucky
Ok. I went ahead and ordered new msd cops, bosh 24lb injectors, it currently has pink injectors in it which tells me it's either 21lbs or 24lbs i guess if it wasnt tuned that could cause the problem? 2 new motorcraft o2s, also got a new manifold gasket it appears whoever installed it used rtv ‍♂ so i guess i could have a vacuum leak there. Taking it to my buddies on monday to replace the janky h pipe flange. I have an sct tuner but for somereason i can't tune it with it, gives me 110be code. Got an appointment for nov 16th for dyno tune so i will probably replace everything up to the injectors to see if that fixes it if not i will just have to wait until the dyno tune to install the injectors i guess.
 
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99N/Afuturebeast

New Member
Sep 4, 2020
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1
28
kentucky
Also i forgot to mention I listened to the injectors via allen wrench and injectors 5 and 6 both seem to sound slower or more sluggish than the rest.
 

Shuttleman83

Active Member
Jun 30, 2019
100
9
28
USA
You know before those new parts arrive, try resetting the KAM (take off neg batt terminal about two hours). Then let it idle about five minutes.
 

99N/Afuturebeast

New Member
Sep 4, 2020
11
0
1
28
kentucky
So all my parts came in and did not fix the rough idle and dying, thought it did at first until i stopped by autozone to get a new hose clamp, decided to get altenator and battery checked. Tested the altenator was bad, until i realized i had left the altenator two wire terminal disconnected. Plugged it back in and boom rough idle again and dying, decided to replace the altenator and still same thing. With the two wire plugged in it acts crazy disconnected runs perfect. I am completely confused at this point.