If it's an old car, a lack of fuel flowing to the carb. So maybe a fuel pump or dirty fuel line.
When the idle goes rough, you must idle the plugs. Else the car plugs roughly.
Yes, and the check engine light should illuminate.
It is a common suspect in contributing to rough idle. See "Related Questions" below for more about the EGR valve, from testing to replacing.
a longer cam shaft will make a car idle rough
What causes a car to idle good and run rough when you give it gas?
Unlikely, Fuel and/or spark are likely culprits.
Biggest problem I can think of is if they somehow make it past your air filter and get back to your throttle body. May cause rough idle, low idle, hesitation, etc. I would think it would take a lot of leaves to really cause a problem, though.
There are many things that can cause a rough idle on this car. The computer could be going out, the engine may not have enough oil, and the engine may not be getting enough fuel or electricity.
Could be the TPS, it will cause it to idle high and low and make the car become sluggish, but a vehicle will run without one, but it will run very rough.
Engine miss or rough idle, or broken motor mount
Yes if it is stuck open.
no