Expert: Sean Halliday - 11/5/2006

Question
Hi i have a 2004 ford mustang GT. I got and engine service light. took it to ford. i got two codes. P0102 - which is the MAF (mass air flow meter) they tested it and they said its good. Also i got a P0174 code, which is i am running lean bank 2. first of all what and where is bank 2 and 2nd what can i do to fix this problem. I have a few modifications to the car and i have an A/F ratio gauge in the car as is and it even shows a bit of a lean condition. The tech at ford said i need to up my injectors from stock, but im still hesitant to do that. i have had all of the modifications on my car for over three months before this condition started. The car backfired for a little while after HARD acceleration. I assumed that was possibly a clogged fuel filter. still not sure. I had a mild exhaust leak that i have since fixed, but the car still runs lean and pops every now and then. On a cold start the car idles really high and takes probably ten to fifteen minutes to calm to a normal idle, if it even does come back to normal.

Answer
It sounds like you have an intake mainifold leak.Thats why the idle is so high .This will cause lean mixture and the backfire.When a vehicle is changed from stock it is advisable to make sure the upgrade is suitable and compatible with the factory components as i have seen engines run completely different once you vary from the original injectors,headers,exhaust ,,etc,,,The bank 2 description is either the right side of the engine or the left,,,ie,,if you have a V8 ,,it may be the right 4 cylinders or the left,,,you will have to pull the plugs to see which side is running lean ,,theyre usually white instead of the coffee brown.You will need to check with a race tune shop to see what you need to fix it.