i have a 2002 FX4 4.6L and after installing a set of flowmasters my check engine has been ever since. i punched out the converters also. has anybody had this problem?

thanks,
mailman

 

There are (4) O2 sensor on these trucks. (2) before the cats and (2) after. If the (2) after that cats do not read a lower oxygen content in the exhaust stream, the SES light will be triggered giving you a reading of a faulty cats.

Obviously since you gutted the cats, you will have to live with this or have a chip burned to deal with it.

 

Did you reset the PCM first? If you did and the code returns you better get the codes read. Might be a lot of things.

Some folks with higher mileage engines get a code for low EGR flow when they open the exhaust up.. This happens sometimes when going to a less restrictive exhaust system because the EGR ports get clogged up with carbon. With more back pressure the EGR gasses are forced to flow through the partially clogged EGR valve .... not so with a more open exhaust. Get the code read and if it indicates low EGR flowyou may have to clean out the EGR ports and passageways.

Good luck. Keep us posted.