help the newbie pls

Get the check engine light checked out at an Auto Zone - they will be able to scan the car's computer for the diagnostic trouble codes. Once you have those codes, post them up and someone will be able to tell you what they mean.


An aftermarket exhaust system itself will not trigger a check engine light, but if you have a loose connection/bad O2 sensor/exhaust leak/etc, it is possible one of those things could be responsible for tripping the check engine light.

The check engine light could also be set off if your car's midpipe has no catalytic converters and the previous owner did not address that issue with the car's computer (either through O2 sensor simulators or through the car's tune/computer). Crawl under the car and find out if your X/H pipe has any cats on it...


Have you removed the passenger side kick panel to look at the car's computer/chip? Do you know what kind of chip/program the car has?

To expand on COBRA90GT, if you remove the computer behind the passenger side kick pannel and pull it out you could see if there is a module sticking out of the port on top of it. If you dont want the tune you could pull the chip out (make sure the battery is disconnected) and run the stock tune. The chip does make a big performance difference on our cars though. I have a Jet chip and removed it once and was amazed at the power difference. One day I will replace it in favor of a SCT LiveWire. Now if you have a Diablo chip or SCT chip and the car has different gears chances are the chip is correcting the speedo for the gear size so you would lose the calibration if you ditch the chip. Did the CEL go on when the speedo stopped working or was it on before that? A faulty VSS would trigger the light but you said the swaped that, so I would check the connections. An off road (catless) x or h pipe will also give the light and in my experience the MIL eliminators sometimes dont work. Usually need a tuner to shut it off. I have a BBK O/R H-pipe and MIL eliminators but still have the CEL for O2 problem. That is yet another reason I want a SCT.

A couple of questions. Did the speedo work at all after dealer installed new sensor? Did the check engine light stay out for any length of time or was it still on when you picked the car up? I can't believe any reputable dealer would charge you for a repair and send the car out no better than when it went in. I would have refused to pay he bill if they couldn't fix it. I am sure the check engine light they tried to blame on the aftermarket exhaust, but there should have been no reason for not fixing the speedo. Personally, I haven't had any issues with an o/r x-pipe or an aftermarket catted x-pipe. With that said, I agree with previous posts by cobra90gt and lasersvt. Get the codes checked and post them. Someone here will be able to help point you in the right direction.