will not show any code. what would be the most common problem?

auto trans

i just put a flowmaster super 10 on my truck and its single inlet dual outlet and i wanna know how much it would probably cost me to run the tail pipe from the exhaust to strait out under my bumper

Do I need special tools toreplace motor and is it time consuming?

Comes back on shortly after I reset the OBD tool.

Where is this and how hard is it to change?

Sqeeky noise when turning while standing, tire edge wear, loose steering.

i bypassed the thermal limiter by unplugging it and switching the fan speed to high and it still does it

replaced fuel filter still having problems

I think My head Gasket is blown. iM BLOWING wHITE sMOKE. hAS THERE BEEN A Re-call

4 wheel drive light flashes but will stop if lights are turned on.Check engine light says on also.

what could be the problem

i can only put 10 characters i cant enter my question with 10 characters

but the truck run good but cel on show code po401

engine needs valve jobs and head gasket