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The P0171/P0172 Codes are there for a reason. Killing the DTC with SCT doesn't eliminate the problem, just the SES light.

P0172 means that the Front HO2 sensor is reading a Rich Condition that the PCM can't trim outside of the set Parameters. (P0171 is the same thing, just on the lean side). I guess you could change the trim maps on the SCT tune, but that won't fix your fuel economy any more than deleting the DTC from the PCM will.

What Sparkplugs are you running? I'm assuming your getting good spark. You said you checked the gapping, but maybe your running the wrong plug types (like going 2-steps colder for a NA Engine) and its causing it to not burn fully..
 

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Grommish said:
The P0171/P0172 Codes are there for a reason. Killing the DTC with SCT doesn't eliminate the problem, just the SES light.

P0172 means that the Front HO2 sensor is reading a Rich Condition that the PCM can't trim outside of the set Parameters. (P0171 is the same thing, just on the lean side). I guess you could change the trim maps on the SCT tune, but that won't fix your fuel economy any more than deleting the DTC from the PCM will.

What Sparkplugs are you running? I'm assuming your getting good spark. You said you checked the gapping, but maybe your running the wrong plug types (like going 2-steps colder for a NA Engine) and its causing it to not burn fully..
Who said anything about killing the DTC? :what: You are assuming too much.

FYI, I went in and corrected the problem with the data logs the customer provided.
 

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FocusSportVP said:
Who said anything about killing the DTC? :what: You are assuming too much.

FYI, I went in and corrected the problem with the data logs the customer provided.
Apologies..

I was under the impression he was thinking about getting the SCT in order to correct the issue, not that it was caused BY the burns fuel maps..

Makes more sense now..
 

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I have been having this problem for a few months now, during that time I have tried everything that I could think of. I have had it to two different Ford dealers, one said they didnt know what was wrong, and the other told me to "not worry about it".

I have since been on my own trying to fix it, I have tested all the wires from the MAF, o2 sensor, frps, and cam sensor to the PCM with a multimeter. They all look fine. I replaced the o2 sensor twice, and I have also replaced the MAF sensor, all of the fuel injectors, the PCM, the pcv valve, the FRPS, and I have tested the EVAP canister by sealing off the purge line. I have searched multiple times for vacuum and pcv leaks but havent found anything. I have searched the intake tubes for leaks as well, and even sealed it all together. Nothing I have tried above has fixed the problem, and I dont know what else to try. I'm at a total loss, and I have no idea what to look at next.

I know the car is running rich, there is black soot on the tailpipe, and when I pulled the spark plugs, it is there as well, and it is on all 4 of them, so I know that all of the cylinders are running rich. And yes, I have checked the spark plug gap as well.

I really hate to even think of this, but if I cant get it fixed soon, ill have to sell the car. I cant afford to keep running rich like this.

As far as mods, I have them listed below, but since I got my new PCM, I havent flashed on the tune. I dont think that an intake, exhaust and throttle body are causing the problem.

Anyone know of any other things that I may have missed?
Check your Cadillac converter that causes that this might be going bad
I have been having this problem for a few months now, during that time I have tried everything that I could think of. I have had it to two different Ford dealers, one said they didnt know what was wrong, and the other told me to "not worry about it".

I have since been on my own trying to fix it, I have tested all the wires from the MAF, o2 sensor, frps, and cam sensor to the PCM with a multimeter. They all look fine. I replaced the o2 sensor twice, and I have also replaced the MAF sensor, all of the fuel injectors, the PCM, the pcv valve, the FRPS, and I have tested the EVAP canister by sealing off the purge line. I have searched multiple times for vacuum and pcv leaks but havent found anything. I have searched the intake tubes for leaks as well, and even sealed it all together. Nothing I have tried above has fixed the problem, and I dont know what else to try. I'm at a total loss, and I have no idea what to look at next.

I know the car is running rich, there is black soot on the tailpipe, and when I pulled the spark plugs, it is there as well, and it is on all 4 of them, so I know that all of the cylinders are running rich. And yes, I have checked the spark plug gap as well.

I really hate to even think of this, but if I cant get it fixed soon, ill have to sell the car. I cant afford to keep running rich like this.

As far as mods, I have them listed below, but since I got my new PCM, I havent flashed on the tune. I dont think that an intake, exhaust and throttle body are causing the problem.

Anyone know of any other things that I may have missed?
Yeah check your Cadillac converter is probably going bad that causes that problem
 
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