What kind of exhaust mods can be made to a 2004 F-150. I had mine changed two weeks (@300 miles) ago, and my check engine light just came on? It's a custom Cat-Back system with a magna-flow muffler, and an air-raid cold air intake.

 

get your comp read and let us know what comes up. its a little easier with the trouble code, also doing a cat back wont make it go off. The o2 sensors are BEFORE the cats and 2 after. the later just helps epa and DOES NOT IN ANY WAY change engine perameters. it will just make the light go bad if your cat is letting too much pollution through the system (bad cat).

 

A warranty can only be declined if the aftermarket part directly caused the problem. In your case check the code and see if its something to do with the exhaust, I doubt it. I'm thinking it's the air-raid. Do a search as I remember members having engine light troubles with aftermarket intakes?? Remove the negative battery cable for 20 min after reading the code and see if the light comes back. Might just be a little flakey.

 

The code comes up it's running lean because of the air raid. Is there a way that this can be corrected? The installer says that it coulb be because the weather got very cold here, (Chicago). If the code gets cleared, will this be a recuuring problem every time it gets cold here? It's not an issue until it comes time for emission testing, (2 years in Illinois), The test must go off OBD here, the light's on, you fail.

 

I doubt it's the cold. Your best bet would be a programmer or chip to remedy the lean condition. You've added more air and the computer can't compensate with enough fuel. Keep the old intake around for your testing. Restore settings to factory, get tested and put the kit and chip/program back on.

 

Thanks for all your help!!!