This is a problem I have been having for a while, and I have tried a lot of things with no luck, but hopefully having more information may help solving it.
When my car is at idle and cold start, it does it's usual thing just fine, no weird idling or anything like that. Once it gets hot though, it is a different story. It will stay running fine because it's in closed loop. But if I turn the car off and turn it back on, it idles very lopey for the first minute of running. It feels like it has a big cam in it. My guess is because the PCM is in open loop. My wideband shows such a high AFR, it doesn't even register on the gauge. After a minute, it steadies out and the AFR comes back down to around stoich, and does its dithering. The effect is that my LTFTs shoot up to 16.4. If I command the car back into open loop again, it will keep loping and the AFR will shoot up again. If I turn the AC on, it will come down to about 17:1.
Also, if I am at a stop and press the pedal quickly, it will almost stall the car.
Could this be anything other than a vacuum leak? I am not sure what type of vac I should be pulling at idle, but I typically see between 17-18 inHg.
