Need help diagnosing a low RPM problem
Need help diagnosing a low RPM problem Hello. So lately, there has been a horrendous "grinding" noise coming from the engine bay. Its been a little faint for the last half-year, but lately, its gotten out of control. Its an 01 Z28 w/an A4. Lemme explain.
If I sit at a traffic light, the RPMs would dip out of control, from the 800's almost to the 500's, almost to the point of stalling. The car will shake slightly, then it will do a quick, but small "rev" of its own, and go back to normal idle for the next 5-7 seconds, and the process will continue. If I very lightly put my foot on the gas from a stop, the car will start to go, and then just die out in power, almost like I took my foot off the gas, and it will start shaking violently, BUT it wont stall. It runs fine under normal and heavy acceleration, but there is still a loud grinding. Also does it at idle. Loud enough where if Im sitting at a traffic light next to another car, I can hear the sound of it bouncing off the other car. The best way I can explain the sound is like, putting an aluminum can thru a meat grinder (i can confirm ive never done that before lol). Its also consistant, and never stops.
Im in the long process of bringing my car back to stock for a trade-in soon, and I would like to get this car running the day I first bought it. So if anybody has advice, please share. Thanks
If I sit at a traffic light, the RPMs would dip out of control, from the 800's almost to the 500's, almost to the point of stalling. The car will shake slightly, then it will do a quick, but small "rev" of its own, and go back to normal idle for the next 5-7 seconds, and the process will continue. If I very lightly put my foot on the gas from a stop, the car will start to go, and then just die out in power, almost like I took my foot off the gas, and it will start shaking violently, BUT it wont stall. It runs fine under normal and heavy acceleration, but there is still a loud grinding. Also does it at idle. Loud enough where if Im sitting at a traffic light next to another car, I can hear the sound of it bouncing off the other car. The best way I can explain the sound is like, putting an aluminum can thru a meat grinder (i can confirm ive never done that before lol). Its also consistant, and never stops.
Im in the long process of bringing my car back to stock for a trade-in soon, and I would like to get this car running the day I first bought it. So if anybody has advice, please share. Thanks
Originally Posted by joshp14
Does it matter if the A/C is on? The grinding happens all the time whenever the car is running or only at idle? Does the car have a tune?
Check your pulleys, if a pulley bearing is hanging up it would make bad noises and might cause the rpms to drop. Mine was doing something similar sometimes when parked sitting idle but it hasn't done it since I changed my idler.
