replace timing chain
you have a cylinder misfire
If the check engine light comes on, have the codes read, they may lead you to the problem. It may be as simple as a faulty coolant temp sensor.
crankshaft sensor going.
Ask this question again specifying what the car is.
the 96 fordwindstar sucks
you pooped in your pants!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
There are pages and pages of things that can cause a check engine light. You need to have it checked with a scantool. Then the code can be diagnosed and repaired.
could be a thousand simple things from spark plugs to bad fuel i usually only have that trouble when using gas from Hess or bp
To much oil in an engine can cause it to flood which will then lead to blowing seals. But it should not effect how the car idles.
It could be a dirty air filter or a dirty throttle body.
you might have a leaking vaccum hose
Motor mounts are bad