Toyota_F1

iTrader: (1)

In an effort to solve my wavering idle issue I'm going to replace the vacuum hoses on the car, 200k miles and midwestern climate haven't been kind to them I'm sure. Idle revs from 1400-2000 in park or neutral but as soon as you put it in drive it's gone. TPS replaced and adjusted but no difference. Any other ideas/thoughts and any info on the right size and total amount of vacuum hose would be welcome.

Thanks.

RA40

iTrader: (6)

I haven't done this for our LS, I did do it on my other Toyota beginning at the 15 year mark. You'll just have to measure the inside diameter of the hoses you'll replace and buy it by the yard and thensome.

If you plan on keeping the car longer, you may also consider replacing weather seals around the doors and trunk for good measure.

justfixit

Have you thought about the IAC valve being defective in some way? Seems to me that bad vacuum lines would affect idle in gear or park alike.
Replacing vacuum lines at 15 years is by no means a bad idea but not sure that is your problem.
Take a pair of pliers and slowly start pinching off the hose that goes to IAC valve. This is the larger of the 2 lines going to the air canister between throttle body and air filter housing. If idle condition improves by closing off this hose I would suspect IAC valve sticking or ???
Good luck

Toyota_F1

iTrader: (1)

The IAC going bad is a definite possibility, I'm getting 2 engine codes, a TPS and an EGR code, can't remember the numbers off the top of my head. But I figured I could just replace the hoses anyway since it costs all of about $2. I'll go mess with the hoses to the IAC and see if anything changes.

justfixit

TPS code is probably 41
EGR code is probably 71
The TPS code is 99% of the time a replacement fix. However if TPS is not adjusted properly it will give code.
Code 71 for EGR is usually one of two conditions. It is usually a leaking vacuum modulator or clogged EGR passages. Simple check for clogged passages is to apply vacuum directly to EGR valve and check for substantial engine rpm loss or engine stall. If neither, then you have clogged passages.
If previous check is ok, simple check for vacuum modulator is one of two methods. Install vacuum gauge on outlet port and verify you have same vacuum coming out as you do going in. You can also remove modulator and see if you can blow through the port on bottom. If you can then modulator is bad.
Good luck

Toyota_F1

iTrader: (1)

That's exactly right, adjusted the TPS and that code is gone, still stuck with the EGR code though. Was getting a tranny code for a bad #2 solenoid but I did a couple runs from 0-65 and it seemed to stop, I wasn't getting 3rd gear, I went from 2 straight to OD and then it would hang there and not downshift, I just got the car so I have no idea when the tranny was last flushed and filled. But it seems to have fixed itself on that one, just a gummed up solenoid?

Anyway, still getting the ramping idle 1400-2000 then back down over and over and over. the little EGR filter was filthy, replaced that, replaced the hoses. Which passages could be clogged? Could still be the IAC I guess, but since it's a $600 MSRP I'm hoping not.

Thanks for the help though, appreciate it.