deuterij

Judging from the number of responses, IACV seems to be the number one reliability issue for these Lexus/Toyota V6s. Our ES300 had it too. Not wanting to tear up too many seal gaskets or screws, I tried the short-cut method of spraying the pintle area and idle air passage with carb cleaner then WD40 after removing the black solenoid cover. It did not give me a good feeling because the design causes drippings to collect at the bottom of the throttle body where the IACV is mounted. It worked for a few months but now the problem is returning. Does anybody know if a puff of grayish-blue smoke during cold starts has anything to do with this IACV issue? I've heard it might be PCV valve. Back to IACV clean-up, it looks like I will attempt a full disassembly and cleaning. The design seems sub-optimal since all crud and debris tends to accumulate in the IACV, but that's just how it is on these Toyotas. I will try to pre-order the seals (thanks for the list of 3 seals, phobang). Smoother transmission shifts might make sense if the IACV is used by the drivetrain ECU to momentarily reduce power during shifts. Excellent contributions, everybody.

Thank you all for the posts. I will try these suggestions. I have also heard the fuel pump changing from low to high mode when I jammed the accelerator pedal. If I listen close to the gas tank, I can hear the fuel pump whine shift from low to high pitch coinciding with hitting the gas pedal. So that confirms that the fuel pump ECU is doing its job. Now whether the pump is actually putting out the required pressure is another story. A defective pump might make the appropriate noises yet still fail to put out enough pressure. I might hook up a gauge to monitor system pressure. I saw the spec pressure in another post somewhere. But thanks again for the help. A new filter and gas additive, then a tune up are in the works. BTW vehicle mileage is 125000.

Looking for help: Problem is that the car hesitates to the point of no power during acceleration. Happens mostly in mid-throttle position with RPM between 1200 and 2000. Seems to clear up above 2500 RPM. Worst when cruising in top gear at about 40 MPH and you try to accelerate. Engine sputters around 1500 RPM and won't surge ahead until a few seconds later or I floor it. I've seen many posts about stalling and acceleration problems with this car. I've tried jumpering the E1 and TE1 leads in the diagnostic connector but that only made the OVD and check engine lights blink on the dash (no fault codes read out on the clock) Then I tried jumpering the B+ and FP leads and that made no difference in performance, so does that mean the fuel pump ECU is NOT the problem? Just before this problem creeped up, I had accidentally tried to start the car with the fuel pump and gauge sending unit disconnected at the tank. I reconnected and the car started but has had this acceleration problem ever since. Is there anything about trying to start the car with the fuel pump and sending unit disconnected that could mess something up? Appreciate any insights. -Eric

Same coolant reserve tank problem here with an SC400. Dealer wants about $400 for parts saying that Lexus redesigned the tank (presumably to correct this common leak problem) and requires that you buy not only the tank but also a new cap and level sensor. I am interested in any less expensive tanks available on the market. Anybody know anything? -Thanks