Originally Posted by OKC-XFR
I was out in Colorado at the CAA this past week - during which I (and several others) noticed an unusual idle issue that developed: if you push in the clutch and rev the engine, the engine RPM's raise up, then drop to around 1K, then raise up to 1.5K to 2K, drop back down, raise back up and so on. Sometimes it will only do it once before dropping to normal idle RPM, other times it will oscillate several times.
Now that I'm back in OKC (1200 ft. altitude), I don't see the problem at all.
Several thoughts on the cause of this problem:
- the altitude is messing with the sensors and causing the computer to 'hunt' for the proper idle
- I did a LOT of engine braking in the mountains - more than I've ever had to do before...maybe this messed with how the computer 'learns' driving habits and caused it to have difficulty finding proper idle speed
- I didn't get a chance to try a throttle reset while I was out there...
Any ideas?
Check for vacum leak. I had the vacum hose to the heater disapear and the idle was fine with the A/C on but when it was off, the engine would idle high if I put the cluch in coming to a stop. Once the car stopped, the idle would return to normal (650-700). Replace hose and idle is fine now.
