2G 2G Fault Code: P0170 Fuel Trim Malfunction

[BIGGSIE]

OK before everyone tells me to search, I have. I've also found a scanned page from a service manual and I have a Chilton's manual. I am an experienced tech and I know what I'm doing (so I thought.) Anyway the list of causes for this P0170 Fuel trim malfunction DTC is:

MAF sensor - Tested ok replaced with a spare one, DTC came back.
Injector - Tested OK replaced all 4, DTC came back.
Intake leak - Pressure tested to find one VERY small leak at TB shaft
have not replaced o-rings yet but I don't think that's it.
Fuel PSI - OK 41 psi base
Coolant temp sensor - OK shows 199* when needle is straight up.
Intake air temp sensor - OK shows 45* on a 35* day.
Baro sensor - OK shows 13.9 (normal)
Exh. manifold cracks - None found.
02 Sensor - Damn Snap-on scanner reads very slow, might be the problem but I would expect a 02 code.

As soon as the CEL comes on the car hesitates on hard acceleration, under boost. Does anyone have access to a "flow chart" for this code? Or any input on what fixed your's?
Sorry for this long post but this CEL is getting on my nerves.

 

[Staytuned]

I had this code once.

I went and removed all wires tapped into the O2 sensor pin on my ECU. I was getting a degraded voltage signal to the ECU from so much stuff tapped into it. IE the blinky A/F ratio gauge and the blue wire mod for the AFC.

 

[romiggsx]

I've started getting this same CEL code (170) for my '95 GSX. I am leaning towards O2 sensor, as the first time the CEL came on was after one of the UIC pipes blew off on the highway(damn mechanics). After it appeared I cleared it hoping it did no permanent damage to the O2 sensor. It reappeared a couple days later, cleared again.... came back a week later. So i assumed I would need a new O2 soon.

Before I could get one, I removed my charcoal canister and accompanying hoses leaving the solenoid plugged in though. The CEL began coming back with increased frequency.
Foolishly I went on a road trip before resolving this, and it started popping up a couple times a day. I am wondering if I have a dying O2 sensor tripping it occasionally and some issue from removing the vac hoses causing it with greater frequency.

I'm curious how many people getting this code have their charcoal canister and vac lines removed. One thing I did when removing the lines is put a breather on the large hose from the gas tank in the firewall instead of plugging it. I'm going to try plugging it and getting a new O2 and I'll let you guys know what happens.

 

[PoorDSMowner]

I am having some troubles with this myself, after reading the posts, I am leaning toward O2 sensors, I haven't messed with any exhaust from turbo-cat so I doubt this would just now happen, but tomorrow I will get a new O2 sensor to see if that does anything.

 

[knighteclipse1]

Upstream O2 sensor was the problem when my car threw that code, replaced and problem fixed. First thing I decided to replace after reading up on the code and possible causes, maybe dumb luck that it was the correct thing to replace.