I have a 2006 Silverado 5.3 and the check engine light recently came on showing code p0442. I have changed the gas 3 times and still comes back on. Now the truck bogs down when you try to bark a tire and some times it seems real sluggish. My brother in law has a 2005 and his acts sluggish but no check engine light on his. Could it be the fuel trim?

Answer: When you that you changed the gas 3 times to try to fix the P0442 code, i assume you mean you replaced the gas cap cap- not the gas. Changing gas will not help with that code. A cap that wont hold pressure is a common cause for a P0442- small Evap emissions leak or P0455- large leak..

The engine bogs down will not have anything to do with your Evap code. You have 2 problems.

A small Evap leak code P0442 can be caused by many things. A stuck vent solenoid, faulty fuel tank pressure sensor, leaking O ring, cracked line, etc. To find the problem, you will need to have a testing pressure station hooked up tot he truck tom look for the leak.

For being sluggish, you need to check fuel pressure. If low that will cause this. You could have a dirty MAF- mass airflow sensor. Poor fuel quality can also be your problem.