Pontiac Repair: 1992 Sunbird runs very rough, vacuum lines, lean condition

Question
Todd,

I have a 92 Sunbird 3.1 MPFI that idles very rough as soon as it starts.  When it gets up to operating temperature, it will eventually die and wont start again until it cools down.  Also, if I keep the engine rev'd up to 3500 after it starts, it blows out white smoke but does not smell like oil (it only does this at high RPM)  I have changed out the fuel pump and it stayed the same.  All of the vacuum lines look good also.  The car only has 47,000 miles on it, could it be getting too much gas?  The code reads clean, only showing code 012.

Answer
Hi Jim:

thye problem with these older cars is the computer systems are slow and are not very good at picking up faults to set codes. If you ahve white smoke out the exhaust it's either condensation/coolant or way way WAY to much fuel running into the engine. do you have a scan tool or just a code reader? if you have a scan tool look at the fuel trim when it's hot and that will give you a indication as to wether it's running rich or lean. low trim numpers are a rich condion and high trim #'s are a lean condition. once you know what what the computer is driving the fuel trim you can start looking for the cause untill then there is no way to tell what's going on with it. good luck :)