my motor when it warms up revs up and down constantly
and just started to do this this week end only has 40k miles some please help. It is a 94 3 gen rx7

my email is fcapo53@rogers.com

Thanks Frank

 

Are you getting any check engine lights?
A number of rats nest solenoids are monitored by the CELs though it won't be able to detect a vacuum leak.

Is the MAP sensor connected?

What's the behavior when it's a cold start?
What's the rev range of the idle when it's warm and what do you mean by warm? (After driving it a while? 5 min in the drive way?)

 

yes I checked map sensor and when it warms up it goes from
900 -1700 rpm.I tried to disconnect the map sensor it revs steady at about 2000 rpm,and when I plug it back in it goes back to the same thing and no engine light.

 

It could be caused by a few things, but IMO most likely a vacuum leak. You said the hunting idle started suddenly and after the engine warms up...that's pretty classic. Start by a close inspection of the lines and ports just after the throttle body. Getting a small mirror and flashlight can help while looking under the manifold.

 

Thanks for your help my is a 94 rx7 can you please tell me
where the map sensor is just want to make sure I'm checking
the wright one.

 

The MAP (Manifold Abolute Pressure) sensor is on a small bracket bolted to the left side of the firewall just aft of the brake booster. It's labeled 'sensor boost' or some such. It will have an electrical connector and one small vacuum line going to the right side of the manifold.
I doubt that's your issue because if that were leaking/disconnected your car would barely idle or run at all. Vac leaks can be hard to track down. If your car has the original rubber hoses they will be brittle from heat and age. So be careful checking them. You're looking for lose, split, missing or broken hose, broken solenoid nipples or open ports. Anything that can leak.

Download a copy of the factory service manual from the FAQ sticky at the top of this section.