It always seems difficult to come up with a descriptive title, and I understand in real world problems are most often convoluted.

Here is the deal ....

On a cold start before the car is fully warmed up, the Throttle reading from the SAFC, which is hooked up to boost sensor/MAP, is 0% when throttle is off, and idle is fine, however, when the car is warmed up, the throttle reading jumps around 10% when the throttle is off, and the car goes lean about high 14s to 16s (AFR), and it idles rough. I just started to have this problem lately, at the beginning, it would settle down after a little struggle at the lean and rough state, but now it gets worse and worse, as soon as the rpm drops when letting go the throttle, is idles fine for about 5 seconds at about 13, then it goes rough and lean. Does anyone got some idea, what this might be?

I do have a exhaust/boost leak, that's getting worse too.

Regards

-X

Oh, it had been raining these days when is started to happen, but now it is a consistent symptom.

 

Any Clue?

 

I think I fingure it out, it was a vaccum hose goes to the purge valve, got to go to test it out. Thanks all.

 

When a RX is started cold, the afr will be approx 1 richer than once the engine warms up to above approx 120 degrees. That would explain why it idles cold ok, but gets lean once warmed up.

It could be a air leak causing the lean at idle. Spray around with starter fluid to find if you have a air leak.

 

check the brake booster line, it can be split/leak

 

Yeah, it is back to how it was now, but I am suspecting there is another tiny vaccum leak somewhere. And I really want to make her smooth all the way. God, the 7s needs attention!

Thanks all