I have a 1996 automatic gxe and recently when i start the car, the rpms jump to 2000 and then suddenly drop to 600 and finally level off at 1400. Normally the car would jump to 2000 and drop back nicely to 1400. Upon this start-up the car will make some type of rumble and/or rattling noise coming from the engine compartment, appearing to be on the right side. I have not done any engine mods intake or exhaust mods as well.

Has anybody had any problems similar to this one? This is all the imformation I know at this time. It happens every so often but its happening more frequently now.

Can anyone tell me what they think it might be?

Any help would be greatly appreciated

thanks,
gmax

 

Clean your throttle body first. If that doesn't settle down your idle at startup, then clean your IAC valve. Search this forum for instructions. See www.motorvate.ca for throttle body cleaning instructinos w/pics.

The rumbling rattling your hearing is probably your timing chain. Chances are the tensioner is not working correctly. I'd get that checked out and or replaced ASAP.

 

My 95 Se just started to make the rattling noise at startup, too, and it has been idling just a tad erratic. I was wondering if it was the timing chain tensioner.

 

I found out my problem, first i thought it was a rattle on the inside but when i rolled down my window i heard the rattling outside which was even louder... so i went under my car and found the problem, for my car it was the part after the cat the bolt had rusted off and the cat was vibrating when i started the car.