I went to go start my car the other day and the battery was completely dead. I couldn't start my car with out a jump. So I charged up the battery and now the car starts up by itself but when it starts up the RPMs drop really fast and after I drive it and come to a stop at a stop light or sign the RPMs drop below 1000 and even drops to about 500 and the whole cars starts to vibrate hard. While being stopped the RPMs will jump around from 900 to 500. Any body know what the problem is?

 

Is the check engine light on? if so pull the codes and post (if you have a 94/95 you can do this from the test box under the hood by the passenger headlight - otherwise you need an OBD2 code reader (socket is under the coin tray). Likely cause is a vacuum leak - check for some of the vids on Youtube but I'd start by looking at the vacuum tree - you need to remove the cover to the throttle cable's rewind wheel - its a single torx screw. look around for any other vacuum line terminations too. Not sure of the connection of the dead battery and the bad idle - any clue what caused the battery to die - ie a light left on (including glove box, vanity mirrors etc)? Did you check all the fuses etc? Check out Volvotips to see tips on how to diagnose. Any other symptoms? Besides vacuum lines, it could be a range of things - ECT (temp sensor), Idle air control valve, MAF, fuel pressure regulator etc. Getting the OBD codes is big help here. You can try cleaning the MAF (with MAF cleaner only) and the IAC but without some more it would be a process of elimination.

 

My car is a 1996 model and no the check engine light isn't on... I went to go look at the vacuum tobing and I found holes in the air filter tobing could that be the problem? Thank you for your replay by the way

 

which air filter tubing are you referring to? the part that goes from near the radiator to where the air filter box is or the boot that goes from the air filter over to the intake (ie through the MAF etc)? If you can post a pic of what you're looking at, that would help.

The tube from the radiator to the intake (it is big like 2" by 3"?) that tends to get holes in it is the air pre-heat that may rub on the hood if not reinstalled correctly - and no that's not going cause a vacuum leak. Mostly the vacuum leaks are those small 3/8 inch tubes that actuate sensors are the ones to look for first.

 

Thank you for your help. I believe I have. Found the problem. One of the vacuum hoses for the PCV system had burst