When I first picked up my 85GSL it idled perfectly at 750rpm. fter about a month or so I decided hack the belt for the airpump because it would make this annoying sound. Since then my idle would fluctuate between 500 and 750rpm. Other than that the car is in tip top shape and doesn't give me any trouble. Is this happening because I still have the airpump there(all I did was remove the belt) or is there another explanation?? Oh yeah btw I've gone to dual alternator pulley since I found one in a junkyard but nothing has changed.

 

maybe a vacuum line.. check there on the air pump... cuz if you got the carb, i knwo they got choke vacuums all over the place.. lemme know.. lates

 

Could be a vacuum leak maybe, but I had a similiar experience. I had just taken off my air pump and installed a racing beat full exhaust, and my car was idling really low. I had to change the idle screw to get it to idle better/higher. I think this had to do more with my exhaust than the air pump, but have you tried adjusting the screw?

 

I haven't tried to adjust anything because other than the idle fluctuating between 550 and 750 the seven runs fine. Once I get back to the states(in kuwait at the moment), I'm going to take some leave and rip out all the extra stuff that I don't want off of my engine. I guess I'll find out then if it was a vacuum leak or not.

 

Could be the idle-kill'n anti-afterburn hose.

http://www.mazdatrix.com/c-5.htm

 

Yep mine was idling low when my hose went out on me, I hate that you have to get it from mazda because of the weird shap and dif size ends.

 

Are you running a cat?