large vacume leak in the intake manifold
You should be around 2200 - 2500 rpms.
check your vacuum hoses check your vacuum hoses
The throttle position sensor (tps) could make the rpms vary.
The rpms need to be high enough to keep the engine running. Most engines need at least 850 rpms to keep from stalling.
NO
Switch to 4th gear!
Yes. Some. But you should have at least 20 - 40 lbs at idle. 60 - 80 lbs when running at highway speeds.
yes,as long as when your warming it up keep the rpms down
i would check the belts they are probably loose or worn
You have a vacum leak. A big one. Check all your hoses. Idle should be under 1k rpms
Have it checked for codes. There will be a misfire code that will let you know what cylinder has the problem.