After I cleaned my clogged EGR tube and IAC, my Maxima is backfiring, out of the exhaust, at initial ignition. It did not do this when the EGR was clogged, and I have double checked all of the vacuum lines around the area where I worked. I am lost as to what is causing this, can anyone help?

 

A back fire in the exhaust is caused by raw fuel in the exhaust system being ignited by hot exhaust gases. Does this happen on a cold start? Are you sure it's not an intake pop, possibly caused by the EGR hanging open?

 

It happens with every start, cold or hot. I guess it could be popping in the intake, but I can hear it coming from the exhaust when it pops (while standing by the exhaust pipe). Would the EGR sticking open cause these symptoms? Because like I said in the first post, it did not do this until I cleaned the EGR tube.

 

Go back over your work, something isn't right.

 

I have, more than once. There was only a couple of things that had to be removed to clean the tube. Everything is tight and sealed.

 

I just realized that if I press the gas pedal and get the RPMs up to 4k or so, it makes the same sound out of the exhaust.