Rough idle on 1996 Buick
A couple of very common causes come to mind with the issues you're having.
1. Make sure you have a clean air filter. ( it is more important than ever before because with EFI, ( electronic fuel injection ), systems, the air is as important to the engine as the fuel ) The computer system needs to be able to get a proper fuel/air mix ratio and a dirty air filter prevents that.
2. Something that you may want to check, or have checked is the, ( MAF ), " mass air flow ", sensor. Some of the symptoms are, bad idle, loss of engine's power, stalling, and eventually preventing the engine from starting, especially in cold weather.
This is usually easy to check;
The sensor is usually located in the air intake duct system,( the duct system that the air filter is in )
between the air filter and the engine. Most have a plug with 4 or 5 wires. Very carefully discon-
nect the plug. If the engine doesn't start either remove the battery cables and clean them very
good, or try to jump start the engine. Once the engine is running leave the plug off and go for a
short test drive to see if you notice the engine performing better.
You can drive while this is disconnected, but try not to do that too long. It can cause other
sensors to trigger the, " check engine light ", and over a longer period of time can damage the
catalytic converter.
Some handy people go to a parts store and get, " mass air flow ", cleaner. It does seem to work
well, but you have to follow the instructions very closely.
I hope this helps you.