fluctuating idle/rich only when cold

[ToBeFrank]

My 99 Solara developed a problem out of the blue. First thing in the morning when the engine is cold, the idle will go up and down (500-1500). Eventually, the idle goes low enough to stall the engine. If I apply any throttle, the engine bogs down and dies. However, if I can get the car to run long enough to even slightly warm up, the idle returns to normal and the car runs perfectly. It is then good to drive for the remainder of the day. I'm assuming a bad sensor, but which one? So far I've replaced the engine coolant sensor and taken the IAC out and cleaned it. Pretty sure IAC is good as it goes full open and full closed when applying battery voltage to the corresponding pins. Any ideas on what sensors I should be looking at next? TPS maybe?

[ToBeFrank]

I forgot to mention I have the V6 and the CEL is not on.

[TRAFFICBLOWS]

Get your throttle body cleaned!!

I had the same problem for '04 thru '06 winter seasons and got it cleaned last winter! No problems now.

Also have your idle RPM checked... my mechanic had to adjust it, too.

[ToBeFrank]

In case anyone else runs into this... I couldn't find the problem so I took it to my indy. The water pump was severely leaking causing the crank sensor to go bad.

[Eye8Pussies]

wow...now that's something that nobody would suspect...but I suppose that could happen...the crank sensor is kinda under and to the side of the water pump...

good to know that that's a possibility. but strange how the CEL didn't come on about the sensor then