Idle - 1990 RX-7 GTU NA
 

Hello,

I tried a search on the forum but I couldn't find anything useful.

My car idles a bit.. weirdly. I'm not sure if it's normal. As far as I can tell, if I just leave it alone, it's idle isn't exactly.. steady. It moves from between 700 RPM to about 1000 RPM, and back. Is that normal?

Also, when I boot the car up, it revs up as warmup. After it finishes it's warmup, it drops down to a normal idle. While doing this, the car drops down as low as 500 RPM (and scares me because I think it's going to stall) and then goes up and does the "between 700 RPM and 1000 RPM" thing.

My car is a 1990 RX-7 GTU NA. It has 175,250 miles. It had a full tuneup within the past year or two (before I bought it). I'm not sure the exact date.

The engine is 100% stock.

-Scotty

was it driven before you baught it? my car doesn't go idle it stalls (83 RX-7) but it hasn't been drivin in almost two years so it just needs a tuneup. If the car hasn't been driven you should tune it, although I would recommend it just to be safe and make sure everything is working right. ;)

Pulsing idle is not normal. Typically, this kind of problem is caused by a TPS either in need of adjustment or in need of replacement. Test the TPS and adjust it to specs (plenty of threads in the forums on this) and then adjust the idle to spec...700-800. If this doesn't solve the problem, you might have a vacuum leak, or your BAC might be sticking. Eliminate the potential causes one at a time.

TPS = Tire Pressure Sensor??

TPS = Throttle Position Sensor...its a sensor mounted on the front of the throttle body that sends a signal to the ECU and when its bad or not adjusted correctly, can play hell with the car's idle. There's several ways to adjust it correctly. Run a search and you'll find a bunch of stuff about the TPS. Also, if you look in the factory Service Manual under the section on fuel and emissions, you'll find information on testing and setting.

i have the same problem, i dont think it would be the tps because no matter what or how to set it to specs it stills idles like that, mine only did it after i put the secondarie block off plate on it might be timing mixed with a couple of other little things , but good luck

If you're confident the TPS is set correctly and you've tried to set the idle, then the next thing to check out would be vacuum leaks. Plenty of places where these can occur. Vacuum lines get loose at the fittings, get baked and brittle by engine heat and spring a leak. Gaskets at the TB, IUM and LIM. After the TPS I would start looking for vacuum leaks. Hunting vacuum leaks is a total pain in the tush.