2011 silverado evap slow leak. HELP Plz.

[eugene12]

Hello, i have a 2011 silverado 1500 WT 2 door standard cab 4.3 engine. I got this reacurring evap code slow leak. I replace the solenoid in back by the gas tank and the purge valve under the hood on the intake also gas cap and just recently the evap canister. i checked all the lines dont see any problems i did recently also get a code for a large leak and replaced the purge valve from a dorman to a ACDelco one and now shows a small leak only again. i did take the solenoid out in the back and hooked it to a battery and it clicks like its supposed too and did the same with the purge valve. at a loss here and sick of buying parts really dont like these evap systems. also at one point it would go 1200 to 1400 miles before it would throw the cel again, now it seems to be every 250 to 350 miles.

[BillK]

Instead of wasting even more money, take it to a decent shop that has a smoke machine and let them find the leak. Then either you can fix it or just let them fix it while they have it. On my 99 Tahoe it was the valve on top of the tank. They found it in about 15 minutes with the smoke

[V12MECH]

Smoke machine is the answer, you can buy one on line from a reputable seller that doesn't cost a couple grand, we have a cheap back up from Harbor freight for our $4K snap on deal. Could be as simple as replacing the gas cap , that could be a leak, also rust buildup on seal point at cap to filler neck. Buy the cap from GM.

[In-Tech]

Yepper to the smoke machine. Plenty of times it is the gas cap. Oil the o-ring on the cap too.