O/R X Pipe causing bad gas mileage

[tylerdred]

I just installed a Borla Stinger catback and a mustangtuning O/R X pipe. I put on a set of used MIL eliminators. I get no check engine light. BUT I am getting horrible gas mileage. I just got 100 miles out of 3/4 of a tank!! I think the car might be running too rich. In park, the car will sometimes die at idle. What do you guys think??? What is the explanation???

 

[TrevX]

I just installed a Borla Stinger catback and a mustangtuning O/R X pipe. I put on a set of used MIL eliminators. I get no check engine light. BUT I am getting horrible gas mileage. I just got 100 miles out of 3/4 of a tank!! I think the car might be running too rich. In park, the car will sometimes die at idle. What do you guys think??? What is the explanation???

An O/R X-Pipe should increase gas mileage unless you have your foot in it constantly like me...I'd be good to get 200 miles to a tank.

 

[tomustang]

I just installed a Borla Stinger catback and a mustangtuning O/R X pipe. I put on a set of used MIL eliminators. I get no check engine light. BUT I am getting horrible gas mileage. I just got 100 miles out of 3/4 of a tank!! I think the car might be running too rich. In park, the car will sometimes die at idle. What do you guys think??? What is the explanation???

what kind of car do you have? (auto/stick?gt?96?03?) need some more info

 

[tylerdred]

More Info

2001 Auto Mustang GT
Borla Stinger Catback
Mustangtuning o/r x pipe
used mil eliminators
nitto 555r's

My gas mileage has gone down the crapper immediately after installing the pipe. I've gotten 100 miles out of a 3/4 tank. I am NOT being lead-footed.

I suspect something is wrong with the O2 simulators and that is causing the car to run tooo rich. Anyone with some info????

 

[FalconGuy016]

That would be what I would say, O2 sensors

 

[COBRA90GT]

No check engine light?

Did you reset the car's computer/PCM by disconnecting the battery during your install?

It's possible that something could be wrong with your front O2 sensors, since the front Oxy sensors are the ones that affect drivability. It might not hurt to get the vehicle scanned for codes if you don't see an increase in gas mileage in the near future...

I know you've already touched on this, but after an exhaust install, it's typical for people to get worse gas mileage initially because they are very heavy on the throttle.

 

[bigblackboat]

I had the same problem after installing my drgas x. I didn't have mil eliminators, so the check engine light was on and didn't think anything of it. I installed my mils and noticed the check engine light came back on. The guy that installed my x pipe damaged the driver side front o2 sensor. The car thought it was running lead so it compensated by dumping more fuel into the engine which resulted in my horrible gas mileage. Make sure your mils are on the back o2 sensors and not the fronts or replace your back o2's with the fronts to check for a damaged o2. Your car should be throwing a code, have it scanned anyway.

 

[tylerdred]

I had the same problem after installing my drgas x. I didn't have mil eliminators, so the check engine light was on and didn't think anything of it. I installed my mils and noticed the check engine light came back on. The guy that installed my x pipe damaged the driver side front o2 sensor. The car thought it was running lead so it compensated by dumping more fuel into the engine which resulted in my horrible gas mileage. Make sure your mils are on the back o2 sensors and not the fronts or replace your back o2's with the fronts to check for a damaged o2. Your car should be throwing a code, have it scanned anyway.

Could it be that the used MIL eliminators have gone bad???? Also, is it normal to have a gas smell inside the cabin after installing an o/r x pipe? I dont think this is normal at all, but I just want to check.

 

[crew_dawg16]

the gas smell is normal, as for your gas mileage, try resetting your computer

 

[bdcardinal]

teh rear O2s have no effect on rich or lean conditions. their sole purpose is to moniter catalytic converter efficiency.

 

[MyEarsHurt]

Thats odd, my gas mileage went up a little when I got mine....well after the first week that is. Cause the whole first week my gas pedal was touching the floor at every possibility just to hear the sound.