Charred Air Filter...help with diagnosis

[mustangaustin34]

Engine smelled a little different than usual and my air filter has burnt marks on the back. Anyone else ever have this issue and what should I be looking for when I tear the thing apart tonight? As always, thanks for the help!

 

[JayRolla]

Major backfiring. Causes from unburnt fuel being pushed through intake valves back into the intake track and igniting. Major misfiring could cause this as if some cylinders are not firing or a burnt valve.
Do you have rough motor? Any CEL's? Do you ever get pops or explosion sounds?

 

[mustangaustin34]

Had a rough idle today: When I accelerated from a stop, the low rpms were quite rough but speeds from 25-50 mph sounded normal, when I tried to pass someone on a 2 lane highway, engine sputtered and the "check engine light" came on for a couple of minutes than disappeared. Parked the 4Runner immediately just in case. I installed a new fuel pump last week but will check everything over again as well as the ignition system (spark plugs, coils, etc). Thanks for the reply.

 

[JayRolla]

See if you can get any CEL's from memory, but if not on then it may be hard to get that code. I bet that is your issue though, whatever is causing the misfire rough idle and sputtering. When your sputtering the fuel is not burning and may be igniting in the intake if the unburnt fuel does make it past the intake valve.

So you replaced your coils, plugs and wires?