Hey guys.
Was shooting P0171 lean system
p0131 02 sensor low volt
p1456 Evap leak
p0170 fuel trim
and the last 1 was a Vehicle speed sensor malfunction code, i forgot to write it down Sorry.

So i went ahead and replaced the cat with a high flow because i had a straight pipe and replaced the bank 1 sensor 1 on the header with a brand new denso. cleaned most of the codes. But p1456 came back and along with a new code p0505 -idle air control system. car runs like **** when its warm up sometime (after driving for about 1+. rpm drop fast when shifting thru gears and when at a red lite it idle at around 1250 and then drops down to 1000 within a 1 minute or so. and sometime it idle at 1500 and car really runs like crap (mostly in 2 gear), shaking when im off the gas. Do i need to clean the IACV? and would the code P1456 EVAP code be related to code p0505. Its retarded because the vss code is gone.

It started to happen after i replaced the timing belt, water pump, thermostat, belts, and replaced the stock fuel fitler with an AEM filter, and the cat and sensor.

Not sure where to start.
P.S. when i clear the codes, car runs perfect. no problem.

Any help would be greatly appreciated.
Thanks!

 

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b18c2?

 

P0505: My guess is that you have an intake air or vacuum leak. If you have an FITV, also clean and adjust it. Does the idle speed change if you unplug the IACV connector?

P1456: Is the rubber seal on the gas cap broken?

 

Yeah its a b18c2 with itr cams and itr headers
i have not yet have the chance to unplug the IAC plug, but will do so tomorrow.

for p1456 i forgot to mention that i have already replaced the gas cap with an new OEM 1. i dont see any gas leaks or smell gas.

 

Sorry for being off topic, i have a fuel pressure gauge, the pressure is reading at around 43-44psi. is that right? i heard its normally at 39-40psi

 

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Bump. any help?