yo whats up guys i have a 89 rex with a 90si motor in it and sometimes the car will warm up and idle around 1000rpm's n other times it will idle around 1600-2000rpm's and than other times it will idle under 1000. so today i was driving it and it was idling around 1600 even after i drove it around for about n hour n than yesterday it was idling around 800rpm's so i was wondering how could i go about on fixing that? the guy at the shop said it could be a vaccum leak but i dont even know which are the vaccum hoses. ALSO when im in neutral at a stoplight or something the rpm needle goes up and down like it will go up for about 2-3 seconds and drop fast and go back up again for 2-3 seconds and do that a couple of times in a minute so wassup with that PLEASE HELP!!!

 

MINES DOES THE EXACT OPPOSITE LOL. RPM'S GO TO 100 OR JUST DROPS TO 0. =/ MY FRIEND HAD TO PUT A PEICE OF TISSUE PAPER SO IT CAN IDLE AT THE RIGHT IDLE THINGIE.

PROBABLY A VAC LEAK OR IDLE SCREW(doubt it might have anything to do with it)

JUST RUN A SEARCH ON THIS. THERE ARE ABOUT 70+ ARCHIVED FILES ON IT. YOU CAN PROBABLY GET A DIAGRAM ON IT. GOOD LUCK

 

Check a few things. First of all, underneath the throttle body there are 2 radiators hoses connected held on by clamps. There object they are connected to is the FAST IDLE VALVE. Take it off, open it up and inspect it. The the piece in the middle screws up and down. Try to turn it to the right and make sure it is screwed all the way in, then put that back on. Don't worry about loosing the small amount of coolant that you do. That valve alone could be your problem.

You can determine if you have a vacuum leak by removing the air intake assembly at the throttle body and then starting the car. Try to block all incoming air to the throttle body by placing your hand over it. The car should shut off. If it is still running with your hand over the throttle body then it is functioning off of a vacuum leak somewhere. You can spray suspecting areas with carb/choke cleaner to see if the vacuum leak is occurring there. You should hear a change in the idle and see some bubbling if you have found the spot.

Also you should find a way to test the resistance on the electronic air control valve which is the thing held on by two bolts to the back of the intake manifold. That is basically what regulates your idle.

Make sure you idle speed was correctly set. That could be causing it as well as a head gasket leak. I know this all sounds like a lot, but I am trouble shooting a similar problem and these steps are necessary. DIAGNOSIS DIAGNOSIS DIAGNOSIS then replace

 

wheres da idle screw located at?

 

what kind of motor do you have?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by manyakiexpi &raquo;</TD></TR><TR><TD CLASS="quote">yo whats up guys i have a 89 rex with a 90si motor in it and sometimes the car will warm up and idle around 1000rpm's n other times it will idle around 1600-2000rpm's and than other times it will idle under 1000. so today i was driving it and it was idling around 1600 even after i drove it around for about n hour n than yesterday it was idling around 800rpm's so i was wondering how could i go about on fixing that? the guy at the shop said it could be a vaccum leak but i dont even know which are the vaccum hoses. ALSO when im in neutral at a stoplight or something the rpm needle goes up and down like it will go up for about 2-3 seconds and drop fast and go back up again for 2-3 seconds and do that a couple of times in a minute so wassup with that PLEASE HELP!!!</TD></TR></TABLE>