Hello everyone, I am new to this forum, yet I have come here for the many problems my hummer has had. I have been struggling with this code for about 4 weeks now. I have put less than 100 miles on the car since I got the code, yet I can tell there is a big different in my idle speed and RPM's. It is rare, yet when I start my car it will click and click until I press on the gas peddle and then it will turn over. As I have done my research the first thing it points to is my purge valve. I tested my purge valve with a hand vacuum pump and it would stay stable at about 6 psi, yet past that it would drop back down. I replaced my purge valve and tested the new one before putting it on and it worked fine, yet once it was on it was doing the same problem as before.


I was thinking the next problem I had is there was a hose that had a leak or it was the control valve that is broken that is letting in the wrong amount of fuel emissions which is why my car runs weird while idling. Please let me know what you all think, I need a smog by the end of the month so I am rushing to get this problem fixed on my own without having to spend thousands at a mechanic.

 

you might have a intake manifold leak with the symptoms you described. check the intake plenum for leaks.

 

That makes sense based off of my symptoms, but how is that related to the code p0442? shouldn't there be more codes popping up and not just a small leak?

 

i dont know maybe more than one issue. but a small evap leak would not behave as you suggest it does usually unless your throttle body and MAF sensors are dirty causing the starting stall and you do just have a small evap leak. the computer usually does not give codes for dirty throttle body and MAF it will just misbehave.but if the intake is leaking it also can behave like a dirty throttle body or MAF sensor. so diagnosis is start with the cheapest issues first like looking for leaks and cleaning. use MAF sensor cleaner on the MAF sensor and throttle body cleaner on the throttle body. for the intake go over the intake bolts and throttle body mounting bolts. and check any hose going into the intake for looseness or cracking. then you might resolve the evap leak which might be the fuel pump has rotted and has pin holes in it.

 

P0442