Originally Posted by RugbyDad
I'm thinking problem 1-4 is trans related and want my wife to run like new. I plan on getting the ECU caps replaced in the future, not the near future just sometime later this year. Maybe before winter. I also want to clean the IACV but can't for the life of me find where it is. After google searches and CL searches I can't find the IACV for the 98-00 ucf20. Pictures? I thought I read somewhere on CL that the 2000 doesn't have an IACV. I think Yamae said it.
Sounds like an AT issue to me too, but you haven't done any of the AT related affairs yet according to your report.
Try doing an AT/Engine stall test as a first step. It should be worked at 2250±150rpm.
This is a bit dangerous to do for a home mechanic though. You need to rock up the rear wheels in addition to use the side brake and the foot brake as well. You also finish it within 5 seconds.
Due to the power supply and the load differences from earlier models, 98-00 models's capacitors last longer. But Toyota has been kept using the infamous capacitors that contain quaternary ammonium salt and those capacitors still fail when used for a long time. You'd better check the ripple first. As long as I have experienced, the first problem was the AT shift problems. Next comes the increased resistance issue of a resistor used in the power supply circuit.
Regarding the IACV, as Doc Yota mentioned, there is none for a 98-00. The main throttle plate and the body pass through the air for the entire RPM range with the mixing air to injectors.