99 Jeep cherokee stalls at red lights in gear. Hard to turn back on, takes a few tries and I have to give it gas. The rmp drop to 500 at idle and stumbles, If it drops lower than 500rpm it usually stalls unless I quick enough to give it some gas.

Any codes?

Could be a number of things, but if "giving it gas" helps get it started, I would first suspect the throttle body and IAC (Idle Air Controller). The IAC is responsible for opening/closing a small air port that controls the engines idle speed. If it is closed, and fails to open quickly enough (or at all), the vehicle will have stalling problems at red lights and sometimes after letting off the gas pedal. "Giving it gas" actually "Gives it air" because the pedal simply opens the throttle body and lets air in. Which can help to overcome the failure of the IAC to let enough air in.

Could be something else, but cleaning the throttle body and IAC (and replacing the IAC if it is in bad shape) would be a good cheap place to start (unless you have more information to share that would change the score).

There is no engine light on. Can there be codes without the light ?
The light did go on for a little and then went off...???

Thank you!1 I will get back to you after cleaning!

I had the SAME issue: Jeep Compass 2007, 2.4L, 4x4, stalling at red light or in back gear. Changed all sensors - didn't help. Cleansed the throttle body- the stalls decreased by 50%; replaced a throttle body with a NEW one- the problem solved COMPLETELY. I did the replacement myself in 35 minutes. The hardest part was to disconnect the electrical connector to the Throttle Body; the old throttle body looked OK (no major rust or any damage, but it definitely did not work as intended. So, the whole thing costed me $90 Can. and less than an hour of my time.