"Service Engine Soon" Light

[lasercobra]

Agree on that point. Those are my A/F numbers and I'm blown... and a rich blower tune at that...

 

[Torch10th]

Agree on that point. Those are my A/F numbers and I'm blown... and a rich blower tune at that...

Exactly...


I got 21mpg average in my 2003 Cobra at 460rwhp/490rwtq. The A/F was set at 11.8.

I got such good gas mileage because I didn't drive the piss out of the car everywhere I went. I could easily manage 100 miles to a tank if I wanted to though.

 

[01cobravortech]

uhh you put a rich tune in your car for an NA application and you like to beat on it. Did you think it was going to sip fuel like a 4 cylinder?

It's all in the driving habit. I got just over 6mpg in my stock 99 Cobra when it was out on track. Obviously you're in it the entire track session but as you can see fuel consumption really suffers when you've got your foot in it.

Add to that the fact that your car is truely richer than it needs to be for an NA application and of course you're going to see crappy gas mileage.

I just can't imagine it guzzling this much gas though, considering that I do a lot of highway driving, albeit at 2800 - 3000rpms. I don't know. I just don't remember the car being this thirsty about 20k back when I was getting between 300 - 320 per tank. I'm not dismissing you, I guess I'm just in total denial.

 

[Torch10th]

The added rpms shouldn't make a huge difference. have you recently instaleld go fast goodies that make you want to push the pedal a little more than usual?


It's also possible that the culprit is in your PCM issue here. If the computer has gone in to a limp mode it might be dumping fuel during normal driving conditions which would certainly account for horrid mileage.

The first thing I would do is get some new oxygen sensors in that thing. Then reset the computer. See if that helps you out.

 

[01cobravortech]

The added rpms shouldn't make a huge difference. have you recently instaleld go fast goodies that make you want to push the pedal a little more than usual?


It's also possible that the culprit is in your PCM issue here. If the computer has gone in to a limp mode it might be dumping fuel during normal driving conditions which would certainly account for horrid mileage.

The first thing I would do is get some new oxygen sensors in that thing. Then reset the computer. See if that helps you out.

I just had the car dyno tuned with the SCT2400 & JLT CAI. About 15k back, I replaced the Bosch O2s with the OEM O2s. I noticed that my fuel economy started to take a dive after putting the Bosch O2s on the car. Then I switched the plugs to the Denso iridiums and I did 2 cleanings with Seafoam 4000 miles apart.

Big question here: Since my tuner just dyno tuned the car and put in a new custom chip making the car run very rich . . . would he be able to detect if the PCM was in limp mode while he was dyno tuning the car? I guess what I'm asking is, is detecting if the car is in limp mode, an easy thing to do with the equipment a mustang tuner has at his disposal?