When im in Drive or Neutral! They simetimes go from 700 to 2500 really fast , and its not consistent!
it happened before and i just had a broken vacuum hose, which i replaced, and now its back!!

what do you think?


(89 camaro Rs 305 TBI, in case someone wants to know)

Thanx,Alex

 

possibly the idle air control

 

I had the exact problem, and I went through the same steps, check the idle air control, the tps sensor, pcv valve (possible letting the vacuum escape), etc... After days and days of trying to eliminate the problem, I found that it was in the electrical system. Then I traced it back to the distributor. It was a cracked magnet in the distributor. So instead of have a single North and South pole on the magnet, it had 2 Norths and 2 Souths. It had been double firing cylinder 2 so the computer was dumping extra fuel in there, which caused it to flood (rpms die off) then the double fire would kick in then the rpms would surge. I would still however check the normal stuff, like your sensors, then look into the electrical system. Hope this helps in your search.

- IROC-Z Racing

 

Thanx IROC-Z Racing. What you said was a part of a problem.
I got it figured out! IT was My distributor!

1) my cap and rotors were old(rusted on inside), probably the guy i bought my car from never replaced them
2) That little gear on distributor itself got loose, and was making noise.

so i bought the whole new distributor with cap and rotor, and now mycar runs great!!!

 

not a problem. glad I could be of some help. great to see your car running well again!

- IROC-Z Racing