Hi, new to the forum and looking for advice with my 99 gl. When I start it in the morning it starts, goes to 1300 rpm then drops to 450-500 rpm and stutters then picks back up to 900 rpm. The car runs pretty decent when cold but if the car idles for a while and warms up the idle will go from 1100 rpm and climb to 1300 every 2-4 seconds and then drop to 600-700 rpm then gos back to 1100. I drove it down my street to a empty parking lot and did a few laps around it and it drove ok for a bit until the idle was jumping. If I let off the gas when accelerating it acts like it stalls, but it doesn't. And when a press the pedal again it jerks violently, and when I drove back it started to putter and jerk and then stall going up a small hill. And it acted like it stalled again so I pulled over and my power steering was working so I knew it was running but when I tried to stop my breaks felt like there was no assist but I can hear the airy puff noises. I scanned the car for code with a generic scanner and I got 5 codes a p1580 and 2 for both o2 sensors-no activity and the heater things. Thanks for any help, love my bug a lot!