wb123

Hello I currently own a 93 mazda rx7.

When the car is in neutral and I rev to about 3k the rpms drop down to almost 0 and then goes back to normal idle point....

Anyone know why the car could be causing this?

Regards,
WB123

Tom93R1

iTrader: (2)

do you have stock ECU?
Might check the dashpot, unless you have PowerFC then there are settings that can fix it.

Bamont

Come to think of it, my 93 RX7 had the exact same problem. I found out that when I bought the car, it didn't have a catalytic converter on it, and was therefore running fairly lean. Ergo, I opted to snag a tuner and it fixed my idling problem.

MrRx

iTrader: (1)

Another possible cause would be your Idle control screw in the TB, or the ICS (idle control) under the upper plentium.

blacksupra94

My car has done the same thing for a while. A lot of people said its not a big deal.

Tom93R1

iTrader: (2)

Oh yeah, is your air pump still on? I disconnected mine for something when I had the stock ECU and that caused alot of similar problems.

Kento

If your engine is totally stock, I'd check dashpot operation first. You may have to do some slight adjustment of the air bleed screw (do a search, there's a couple of threads that have a photo of its location) or the idle adjustment screw.