New issue manifested itself this morning while exiting the freeway on my 99 RS. At the end of the off ramp was a red light, so I slowed and put it in 2nd. It turned green before I could stop all the way so I accelerated, but felt a hesitation or a bogged feeling. I also heard a weird noise from the rear end, almost like a "clunk". I took it for a spin again at lunch to see if it was still happening. Seems to idle real rough, and also hesitate in all gears. Also didn't really want to go any faster than 65 in fifth gear. About 78,000 mi on it. Any ideas guys?
Was it a dull clunk? or more of a sharp crack? have you looked under the car yet? to see if things are still held in place like they should be. (ie diff stiff attached, driveline is still there, ect....)
It seems to me that a sensor blew and needs to be replaced. If it's really bad, it could be the MAF sensor or the knock sensor. The MAF will cause knocking and hesitation and the knock sensor will cause hesitation in the mid-range. Sorry if I can't help more.
yes, you should get a CEL for the MAF sensor. it could also be an o2 sensor. if it blew out or something. but that would cause extreme hesitation. i don think it would affect the top speed though. that would also through a CEL. however that clunk form the back end doesnt sound like a MAF problem, and not really a sensor either (unless it blew out and hit the underside of the car, which is very unlikely) is your CEL on? if it is i think some palces like Checker will check it for free. other wise my guess would be something mechanical like the rear diff, but that wouldnt affect the idle since its in nuetral.
Another thing, when I owned my 00 Impreza RS, it's front O2 sensor went out and made the car run in limp mode. It was a common problem with the 00 RS's. This caused a lot of hesitating and limited my top speed.
I think I found the problem. 1 spark plug cap was loose, almost falling out. Secured it and the simptoms went away. Thanks for the help guys!
I get the same thing too, but I don't hear that clunk noise. It happen often in 2nd gear, if i'm slowing down to a stoplight and when the lights turn green and i'm still in 2nd gear and i step on the throttle, then it hesitates(it jerks sometimes, sometimes it jerks hard), and if i'm rolling on the freeway/highway going 50-60mph in 5th gear. Once i let off throttle losing about 3-5mph, then stepping on the throttle again, it hesitates I own a 98RS, mods are borla header, stromung catback, had 1 CEL fixed it, and i also have a 96 Legacy intake
If you need one I think I still have a couple working MAF sensors from a MY99, but they're pre-recall units.
