My 86 monte LS 4.3 TBI hesitates or stumbles when I hit the throttle. This has been happening for the past 2 years but only during cold temperatures. When the temp is above 40 the car runs like a top.
It happened again last night, I started the car and it idled a little choppy, when I put it in reverse and gave it a little gas it died. I started it and let it idle for 5 minutes and was able to ease it home even though it ran rough like it was going to die on me.
Any ideas what could be causing this? Again, it only happens when it is cold out, during the summer months it runs just fine.

try your coolant temp sensor.
or air temp sensor if so equipted
or mass air flow
hope i helped