Just replaced my engine in my 93 gmc yukon (350 small block) ran fine for the first day i was driving it around, second day when ever i got to a stop light it would idle real low then if the light was long enough it would stall out if i didn't give it any gas. I just replaced my fuel pump and fuel filter about 2 months ago, along with my air filter. I don't think I have a vacuum leak because i can not hear any hissing. any suggestions? Thanks.

 

Still may have a leak. When it's cold it should have a higher idle, that's when I'd spray some carb cleaner or brake cleaner over the vacuum lines & see if the idle changes. If it does - there's your vacuum leak!

 

Does start right back up easily?

 

yeah it starts back up without a problem i just gotta give er some gas so she doesn't stall out

 

I tried the brake parts cleaner over the lines and nothing changed.

 

TBI right? Sounds like it's flooding itself to me. There's a way to check the spray pattern from the TBI. Temp sensor could be telling the ECM the engine is still cold and therefore causing a rich condition. Mass air flow could be diry/confused. Not sure if a faulty O2 sensor could cause this. The DIY section explains how to diagnose some of those.

 

Yeah its tbi, and I'll check the temp sensor, I do not have a maf sensor, they started putting those in 1996 and up. I have a 93. I'll check the sensor though