I recently got a 1988 Mazda rx7 fc as my first car! I don’t know a lot about rotary engines, so I need a little help. My rx7 has 91,000 miles on it and starts fine and idles well but sometimes when I am driving it drops rpms for a second or two, if I switch gears it goes away for a little bit but starts again. I normally pull over and turn off the car and let it sit for a minute and start it back up, and the problem goes away for while I’m driving. It happens infrequently, I’d say every few days or so. I know this is not a lot of info but if anyone out there has had a similar problem and know what it is please help me out and let me know what might be wrong!

 

Is it actively while you’re moving, or while idling at a light?

 

it’s when I’m driving the rmps will drop and the car shakes a little bit. If I give more gas nothing happens. Hope this gave a little more info!

 

TPS, fuel system, intermittent ignition

 

My '79 S had a similar problem. I traced it to my two teen age sons and their version of a credit card - a syphon hose that they let slip and drop into the tank. While driving, the fuel would slosh around moving the hose. It was just the exact diameter to block the fuel pickup tube effectively shutting off fuel delivery to the engine. Not likely your problem, but strange things do happen and should not be overlooked.

 

I wonder if this is the secondary injector hesitation. Next time you go for a drive, accelerate the car up the RPM and notice if it happens around 3,800 RPM. If so, it could be a number of things, ground wires, injectors, fuel filters.

 

I would check the TPS using the OHM method and a digital multimeter. This is often the cause of such issues.