Hi. I'm trying to help my bro in law with his truck. He has a 98 sonoma 4x4 with the 4.3. It starts fine but when you put it in gear and try to move it it stumbles badly and almost refuses to take throttle. We pulled the codes and it shows MAF or VAF low input and EVAP low imput. We changed the MAF and then the only code is the EVAP. Now we can't figure out what to do next. Any suggestions?

 

I have had that problem with one of my vehicles(dont remember which one, I've had 12in 4yrs), it turned out ot be a pluged fuel filter. I would try that its cheap enough.

 

I would also check the pvc valve.