Some background on the car: 1994 w/ ~70k daily driver. Only get over 3.5k rpms maybe once a day passing a car, but never close to redline. I have had a strange problem that comes and goes from time to time over the past 2 years. When at a constant speed < 3k rpm, the car will lurch back and fourth, but is fine under acceleration. It has been doing it MAYBE one day out of every month. On my last oil change I switched to synthetic. I have also had some wear on both belts. A few days AFTER the oil change I crank up and get a horrible idle. Quickly shut it off and check belts. They are intact. I drive straight to sears and have both belts replaced. It idled fine for one day and every day since then the idle has been bad at start up. I can rev it to 2k for 20-30 sec and it idles fine. However, at about every other red light it will idle rough. I checked the MAP sensor and it if I am looking at the right thing, it is in fact plugged into the firewall, nothing visibly loose. I am prepared for the worse, but could it be something else such as the synthetic oil or spark plugs? Thanks in advance for helping this noob.

 

i would try to hook up a wideband to check A/F....possible an injector is failing on you....just a thought.

 

Is your airpump engaging? If not, it can affect your idle and throttle response. Also, if your TPS is out of calibration, that can cause problems you're describing.

Oh, and you really ought to redline your motor frequently. It's actually good for the rotary and you can damage your motor (carbon buildup) if you don't.

 

idle rough as in whole car is very shakey? or idle rough as in the rpm jumps around?
i would try changin back to non syn engine oil

 

I would say TSP out of wack. but may main concern is why are you taking an FD to sears to have work done?.

What are your mods?

Jeff

 

What you describe could be the 3k hesitation that lots of people have. It could also be a problem with the airpump (blown fuse maybe?) or TPS. I would suggest checking all of your fuses, then all of your grounds. Sometimes people have been able to get rid of the hesitation by adding or replacing grounds.


Oh, and I wouldn't recommend taking your car to sears or even the dealer. A reputable rotary shop is the only place you should go, as most mechanics in these places don't know enough about 3rd gen RX-7s to be of any help (they usually cause more problems).