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Discussion Starter · #1 ·
I have a 01 paxton supercharged cobra that I was letting my brother use while I was gone for about a year due to work. When I got back the car had a check engine light for p0172 and p0175 (Running rich) Well apparently while my brother was driving it he said he kept noticing oil mist on the valve covers every so often so he would just refill the oil instead of replacing the cap until I got back. So I did the spark plugs about a week ago and noticed they had a lot of oil in the 1st to. I assume it was just him overfilling the oil since there was no indications of a bad gasket.. Well the car ran fine for a few days after that and cleaning the maf sensor (It had a rough idle sitting about 200-300ish rpms higher then normal when warm beforehand) then the code appeared again so I replaced the maf sensor (It was using a termi/lightning maf) and now 2 days later I am running lean (p0171/p0174). The previous owner of the vehicle got the supercharger installed and I guess there was no room so the K&N Air filter sits just in front of the passenger tire probably like 6 inches or so off the ground with the maf sensor probably another 6 or so inches above that. I am pretty new to the whole forced induction thing so I don't know if it just requires a tune or if there is something else I should be doing but apparently it has not ran lean up until now. Any help/Ideas would be appreciated.

TLDR: Supercharged car was running rich p0172 and p0175 so I replaced the spark plugs and cleaned the maf, until the CEL returned back a few days later and then I decided to replace the maf now its running lean.Any help/Ideas would be appreciated.
 

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1986 Ford Mustang GT
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Well for starters, what kind of MAF did you replace your Lightning MAF with? If it is not tuned or calibrated, it could be sending the computer the wrong metering for fuel, making the engine lean. You don't want to introduce more variations into your problem to make it any more difficult.
 

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1986 Ford Mustang GT
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So you went from one MAF to another but the exact same thing, and got a different outcome. Something doesn't seem right, is there a chance that the previous MAF was calibrated differently? Maybe try putting it back on?
 

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Discussion Starter · #5 ·
Yes that is correct. I have owned the car for about 4 years and about 6 months after getting it I took it to a shop in Phoenix and they tuned and dyno'd it and it ran fine when I had left a year ago. So I was not sure if was it because I just threw it on without taking it to get something like that done. Or if it was like the K&N filter since it sits so low to the ground that it might be causing the maf to get
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dirty?
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Discussion Starter · #8 · (Edited)
I have not did done a smoke test or changed the o2s since I have gotten the vehicle so I am not to sure on the age I ordered a full new set a few days ago so just waiting on them to come in. No wideband. You think smoke test the next thing to do after the o2s? Also just noticed the fuel pressure gauge is not working anymore apparently it just sits at 0 regardless of load.
 

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2003 Mustang Cobra
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460 Posts
What is your PCV valve or catch can situation?

You could be sucking oil from the valve covers

Blow off valve or bypass valve?

That is a normal place to have the MAF and filter on these cars
 

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Discussion Starter · #10 ·
Checked the catch can and it was mostly empty about a tablespoon of oil.
I have a blow off valve as well instead of a bypass.
o2s got delayed and will not be here until Saturday sometime
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, I put the old MAF back on meanwhile until I can figure this out.
 

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Discussion Starter · #11 ·
Changed all o2s and same issue still persisting. This is at 80mph on cruise control (old owner put gears) before he had the supercharger added and I just have not had time to get them lowered
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What do your 4 o2 sensors voltages show?
 
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