i have a 95 Z28 A4. I am having surging problems at idle and sometimes at speed. When i start the car it will rev up to about 2000 rpm and then drop to 200 and sometimes dies. at red lights it will sometimes try to go while i have my foot on the brake. i replaced the TPS sensor and it didnt fix the problem. i have recently replaced the opti, plugs and wires, and the fuel pump and filter. i have heard it could be injectors, regulator, o2 sensor, and the lates is they think its a busted computer PCM. i am not nor have i ever got a legitimate serive engine light. it has blinked on and off every now and then, but when i have it scanned it never shows a code ever been given. does it sound like i need to replace the computer? or is it something else?
thaks for any help
Chris

 

Look at the spring that shuts the butterflies on the TB. I'm not exactly clear on your problem, but my old Z did that. It would idle way up there, it's like haveing cruise control on. I got a dayum speeding ticket cause of it Hope it helps!