when i start my car the rpms will jump real high and stay for a few seconds, then it comes back down to where the injectors come back on then it jumps to about 2500 rpms then back down and jumps back up to 2500 and so on. when i give it the slightest amount of throttle it revs so high and doesn't want to come down immediately. i just recently installed a new intercooler but didnt mess with anything else. i checked the tps and vta1 closed was off a little bit. i adjusted accordingly to mazda specs. the volt. looks fine. wires look fine. checked all connections and they seem to be fine. the butterfly seems to be fine. i don't know what else it could be. it first started when i was accelerating at a light. i wasn't hard on the throttle, just normal driving. any suggestions would be great. thanks.

 

Not sure w/ our engines, but I had a piston engine (Integra) that did the same thing. The air/fuel adjustment screw was loose and was way out of wack. My mechanic adjusted it and all was well. Might help, might not.
Ciao

 

Check for vaccuum leak between engine and throttle body. My PCV line broke the other day and the symptoms were very similar.

 

i checked all the vaccuum lines but i will check them again in the morning. i thought i have been over everything. thanks.

 

If you still have your idle speed control (ISC) on the car, it may be hung open. It causes the idle to surge as you describe. Being as you put a new intercooler on the car, you may have introduced some small debris into the intake that landed in the ISC.

 

1. Idle screw on top
2. The fine adjustment screw located under the TB. (I forget what that's called).
3. Check your throttle cable.
4. Check the butterflies on the thottle body
5. TPS
6. ISC (It's probably this)

You can also search "Hunting idle" if you want too as well.

 

ITS A HUGE VACCUUM LEAK SOMEWHERE UNDER YOUR UPPER INTAKE MANIFOLD FIND IT AND FIX IT

sorry for yelling

 

Had same issue years ago, seems some packing foam was down inside the IC and once installed and started got sucked in and caught in the ISC.
Also as stated above check the buttery fly in throttle body. Sometimes they can get dirty and get stuck open a tad causing this.

 

Alright thanks guys. i figured it out yesterday. piece of debris in the buttlerfly which i didn't see before. I appreciate the help.
Someone close this thread, its done...