i recently cleaned the iac valve and intake filter, as well as flushed the cooling system of my 96 xj because of a high idle and high temp. it's idled great since i cleaned everything up, but this morning as i got up to about 40 mph, the jeep started lurching and shaking while i was driving. it also started revving up every time i put the brakes on while in drive. after a few minutes of this, a warning light came on that i've never seen before: "GEN" in red letters in the middle of the left side of the light panel. owner's manual says there's not even supposed to be a light there lol. any thoughts on what might be the problem?

 

update: i just tried driving it and the thing stalled twice. battery gauge is floating just above the red zone and the lurching has gotten much worse. i’m thinking it could be that my alternator has all of a sudden gone bad. thoughts?

 

There is a mix of symptoms there that don't seem like they could -all- be voltage related. But certainly this calls for a basic battery and system voltage test. Do you have a multimeter? What are the voltage values across the battery terminals (not running, as well as running)?

 

Done this myself. If you sprayed cleaner into the intake, you likely took out the throttle position sensor.
If you have a scan tool you can look at the waveform, or, test with a multimeter.

 

Does it keep jerking when let off the gas and coast? Anyway just check this in case, it's free.

Your brake light switch. It's under the drivers side dash near the brake pedal. Make sure the plunger ain't stuck. See picture below.

 

thanks for your suggestions everyone! i ended up with a dead battery by the end of the day and barely made it to my local parts store after getting a jump. the guys there charged/tested my battery and told me my alternator needed replacing, so i took it home and replaced it. that seems to have fixed all the problems i described above. i’m so glad it was such a simple fix!!

 

Is that not indicating a failure to detect 12V at the "Alternator Warning Light" ?

my presumption would be your vehicle is loosing all voltage, due to faulty battery, alternator, or wiring. Check all relevant terminals & grounds