How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15201
Experience:  GM Grand Master Technician 2007. 14 years experience.
Type Your Chevy Question Here...
GM Tech (Cam) is online now
A new question is answered every 9 seconds

99 chevy tahoe: 5.7L in my bay with a p0442 small evap leak..gas cap

Customer Question

I have a 99 chevy tahoe 5.7L in my bay with a P0442 small evap leak. gas cap tests fine. I have pressurized the system, system holds pressure, i have also smoked the system. still no evidence of leak. started vehicle, sealed vent and opened purge to put system under vac. and monitered the tank pressure with snapon solus scanner. vac does decay about 0.50 mmHg per minuet. according to service info any decay in 15sec will set code. do i have a significant leak, how can i pinpoint the location of leak if it is so small and only under vac? or could it be a sensor, or pcm?
Submitted: 7 years ago.
Category: Chevy
Expert:  Gentry314 replied 7 years ago.
When you cleared code did it come right back?
Customer: replied 7 years ago.
yes with in 3 days