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Discussion Starter #1
I want to find out whats wrong with my car. My AEM Wideband shows 11.9-12.8 AFR on stock 93 octane tune. Doing the fuel pump rewire mod didn't really drop my AFR's, maybe 0.2 at the most. Adding the fuel through DSP I managed to lower AFR's to 11.6-12.2 Or lowering the boost I also could lower my AFR to the same range. Question is why it runs so lean out of the box? Canned DSP 93oct should be at 11.7 and should not be running lean for stock SRT-4? The only mod I have on my car is HKS BOV and pink and blue lines are disconnected and capped and AEM short arm intake. Everything else stays stock. Anyways I decided not to touch boost levels and add fuel between 5-6 and 6-7k. I managed to get 11.6-12.2 AFR. Hovewer I decided to install walbro fuel pump 255 for my future upgrades, it didn't really effect on AFR after installation. Then about two days ago, out of nowhere I noticed that my AEM Wideband gauge shows 12.8-13.8 AFR's at the WOT. What can cause your AFR go so lean if all fuel mods are done and it's a STOCK car??

Can PCV valve cause bad AFRs?

Maybe HKS holds the boost when mopar used to leak and that leads to high AFRs?

O2 sensor is bad ?

Bad pump or bad stock FPR??
 

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I don't see a replacment fuel fliter on your list of items. How many miles on the car? The FPR/filter should be replaced every 30k miles and it gets missed all the time as a normal maitinence item.

Next, the 93 tune comes lean from DS but not 13.0 lean... something is up.
 

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Discussion Starter #3
Usually I never seen over 12.8 on stock canned 93oct tune and that was at 5-6k rpm range but at mid range i'v seen 11.9-12.3. I never replaced fuel filter or FPR and my car has around 80,000 miles. And i believe previous owner never replaced it before too.
 

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Usually I never seen over 12.8 on stock canned 93oct tune and that was at 5-6k rpm range but at mid range i'v seen 11.9-12.3. I never replaced fuel filter or FPR and my car has around 80,000 miles. And i believe previous owner never replaced it before too.
That would be the problem (suspect). I would replace that and see if it gets any better, we have them on the shelf, standard is shipping 3 day air.
 

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i was running mid 13 AFRs w/ the canned tune at first also. did the fuel rewire, fpr, and s2 injectors all from ptp and now i'm running low to mid 11s w/o adding fuel via dsp (spiking 22ish psi). i could run flat 10 AFRs w/ fuel maxed out on dsp.
 
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