I've had a 2zz swap for awhile now and started having problems with a very high idle. My idle, after already being warmed up, would do a slow raise from 1000RPM to 2500RPM and back down, and repeat. I took it to a local shop for repair. The found that there was a intake leak, in which the MAF was loose and air seeping in. Another thing they did during this repair was lower the idle itself on the throttle body. While the idle has been steady since getting it back, the car exhibited a new problem. Anytime driving over 4000 RPM there is a sudden boost is power. Then when bringing the idle back down it's very erratic, jumping from 1500k to 2500 until it eventually dies. Does anyone have any insight as to why the car would run normal at lower RPMs, then jump in power after hitting 4000 rpms with the idle all of sudden becoming erratic? I've been able to repeat this continously with the steps below:
- Initially starting the car everything seems ok. Temperature of the car doesn't seem to matter (i.e. cold start or warmed up). While the car is warming up, VVTi switching on can be felt consistently at 4500 RPMs.
- Easy daily type driving shows no problems. I'll drive with steady acceleration, with the RPM's never going above 4K. The idle is stable, and remains at ~1200 RPMs. However, it is EXACTLY at ~1200 RPMs. When I first got my cams in, the RPMs would have a constant/slight fluctuation?
- After the car has completely warmed up is when the issue seems to occur. If I bring the car's RPM's above 4K RPM's, the VVTi doesn't seem to turn on. I've tested this at both 50% or at 100% on the gas pedal, separately.
- If I keep the RPM's in 4000 range for several seconds eventually there seems to be a be a boost in power, with the car lunging forward for a second (it feels like the VVTi all of sudden turns on?) @ 4000 RPMs. I've been able to repeat this using either 50% or 100% on the gas pedal. During a test drive with my co-worker he initially thought the 'lunge' was me hitting 100% the gas pedal to try to make the issue happen, but at the time at had kept it at a constant 30%. After the 'lunge', it feels as if the car has a 5% increase in power through the entire range of RPM's.
- During this time when I let go of the gas, RPM's are now slightly erratic, and the engine is louder and more throaty (the way the car was when I first got my cams installed). The car has 5%-10% more power as well, and is much more responsive to the gas pedal. On occasion (at least once a day) the idle becomes unstable, jumping around from 500 RPM to 1500 RPM until it eventual dies unless I level it out using the gas pedal. Once I level it out the car runs normal again.
- As soon as I restart the car idle is back to normal, but back to the original power, and without the obvious feeling of the VVTi turning on at 4500 RPMs.
- I'm able to repeat this issue with step #3.