[Aquarius]

Hey guys,

I bought my 03 GT last summer and it came with BBK long tubes which I believe are the source of the problem. The CEL came on 2 weeks after I bought the car and I had to bring it back to the dealership about 5 times because each time they said they fixed it, it came back. The dealership actually outsources it's Mustang work to a local race shop and its an hour away which makes these frequent trips a real pain in the a$$. They replaced all 4 02 sensors. I do have MIL eliminators installed. After the last time the light came on (late August 07) the guy at the race shop said he was all out of answers. He put a custom chip in the car, but left the rear 02's on so I'd be able to detect any problems. I saw him the other day and he said that he legally cannot turn them off now or he'd get in huge trouble if he were caught.

The current codes are P1151 and P1131, both lean codes. Seeing as its sensing lean, is the engine now overcompensating and injecting more fuel to correct it? Is this why my gas mileage sucks (12MPG)? I burn almost a 1/4 tank of gas traveling 60 miles round trip to work everyday. One of my cats blew out last week too, perhaps too much uncombusted fuel in the exhaust melting it down? My biggest question is how can this be fixed? I was told a) either remove the long tubes and put stock headers on, or physically move the 02 sensor locations. I'd prefer not to do either of those. I know there's plenty of you out there with long tubes, so what have you done for this? There has to be an answer somewhere?

[MATT02GT]

You do have the mil's hooked up on the rear O2 sensors right???

[00vabchgt]

you need a tune to adjust the sensitivity of the O2 sensors. what's happening is that the exhaust gases are cooling off too much before getting to the O2 sensors because the long tubes put the sensors further away from the head. if the car (thinks) it's running lean, it will add fuel to compensate, and yes, that will affect your mpg. i had problems with the car stalling, bucking and just generally not running right after i got my long tubes installed. i went to my tuner and he fixed me right up. not a problem since...

[Aquarius]

Who's your tuner?

[00vabchgt]

i go to Dynotuned Performance in Chesapeake, VA. Brent did a great job on the tune...

[Aquarius]

Correct MIL eliminators on are the rear 02's.

[MATT02GT]

You probably just need a tune for them would be my guess.

[cliffyk]

Here are the possible causes for those codes (same potential problems as P1130) from the factory manual.

The O2 sensors are heated, however the heaters are controlled by the PCM according to a series of calculations, none of which involves the actual temperature of the heater. Because of this it may well be as 00vabchgt said, that a good tuner can alter the heater control parameters.

Another solution might be to install older 6.0 Ohm heater O2 sensors that can be powered all the time (the newer 3.3 Ohm heaters heat up faster but they will burn out fairly quickly if powered all the time).

The Bosch 13275 is a good 6 Ohm heater sensor, you could install a couple of them and wire the heaters to a source that's hot when the engine is running.