My rx7 runs great, but after I start driving her, when we are stopped at a light or something the rmps, boost guage, and pressure gauge, start to spaz. The rpm will go spike to 1200 then drop to 800 and repeat every second or so. The boost guage will go from -10 to -12, and the pressure guage will go from 60 to 40. I can post a video if that description isn't good enough. Should I be worried about this? I just assumed it's something needing adjustment with the throttle body or something .. But would like to know what other people think!

 

Sounds like you might have a vacuum leak or a problem with your idle control valve.
What happens is that the ECU sees the rise in idle and tries to maintain a pre-set value like 800rpm. When RPM's rise above a certain threshold the ecu cuts fuel the rechecks idle goes up again fuel gets cut idle drops then rises then drops and so on.

Make sure you don't have any vacuum leaks, check your MAP sensors as well and you TPS sensors voltage.

Make mention of any mods you have as well.

 

+1 on vacuum leak. Spray some carb cleaner or starter fluid around the engine to confirm.

 

So is it bad if there is a vacuum leak? is it fine to run with a leak? Iv read some post where they force a boost leak to go easy on the motor. And I installed the boost guage not too long ago and this just started happening so maybe the rubber lines might be punctured?

Mods include:
3 inch downpipes
1 cat
Aftermarket muffler
New motor and turbos
Apexi tuner and ecu

 

What would carb cleaner being sprayed around the engine do?

 

If theres a leak, youll notice a difference in the engines idle.

Dont start a fire tho...

 

Post a vid. Much better

 

Were all vacuum hoses replaced when the engine was rebuilt? How many miles on the rebuild?

Sounds like a vacuum leak to me.