2002 Ford F-150 engine running to rich

Tiny
HAMMER_JACK
  • MEMBER
  • 2002 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 54,000 MILES
Hi, and thx for having the time to ask my question. I have a 02' Lighting that I bought used. Since I had it the truck has been running rich. I know for a fact that it has a after market exhust and that one of the pulleys on the belt has been change. Also I replace the air filter to a BBK cold air system. I took the truck to several shops and there saying that the O2 sesors are reading rich, banks 1 & 4. I was going to buy a flash tuner to change the PCM and get rid of the check engine light off but would that fix the problem? I need to fix this because I have to take my baby back to inspection by June. THX
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Tuesday, April 1st, 2008 AT 3:07 PM

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Tiny
BLACKOP555
  • EXPERT
You should switch the bank 1 and two sensors and swap them, if the code goes with the o2 sensor then the sensor is bad, if not its engine related. Check to make sure the injectors are not leaking or the fuel pressure regulator is bad. Also check the MAF sensor.
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Tuesday, April 8th, 2008 AT 5:35 PM
Tiny
FLEXY5
  • MEMBER
I'm not too familiar with the BBK filter set-up. If it is anything like the K&N filters that require being treated with oil, then I would suspect the MAF sensor. The other thing you mentioned that I have seen before is the modified exhaust system. If you have modified cat converters or no cat converters at all, then the downstream O2 sensors are not sending the signal that the computer is expecting. This can cause a rich condition on the upstream O2 sensors. Find out what they have done to the exhaust and if there are even any downstream O2 sensors. I've even seen installers use a shunt and leave out the O2 all together. All this info will help us determine what's going on. Blackop555 is correct, though, check the obvious first and then consider the obscure.
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Tuesday, April 8th, 2008 AT 10:25 PM
Tiny
BLACKOP555
  • EXPERT
Leaving the 02 sensors are a problem all too common when using after market exhaust. But id be checking the MAF sensor first, since aftermarket air intakes are known for this.
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Wednesday, April 9th, 2008 AT 7:19 AM

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