CAfast

alright...My 93 LS400 has a weird problem that is confusing me. Sometimes after driving a while the cars idle will go from normal rpm to surging to 2K and above. It happens out of nowhere. Sometimes I can go to work (about a 15 minute drive) and it will not happen. Other times it happens usually at a stoplight. During this time, i have reduced power from the vehicle and it feels like it is going to stall. I checked for vacuum leaks and found the two vacuum lines going from the throttle body to what i think is called a vacuum switching valve were a size too big. So i replaced those and it ran fine for a while. Then it started to do it again. I noticed that the line from the power steering to a junction on the intake tube is broken off. I havent replaced that yet. i drove the car today and It began to surge to 2k rpm. I got to work and turned the car off. I tried to start it back up and it would not start. It just cranked. After a few tries, it starts back up and is idling at about 2k rpm and bounces up and down. I took it out for a drive and I get to the stoplight (full stop) then I go to take off and the car dies when I step on the gas. I try to start it up and it just cranks. After a few more tries, the car starts and is still idling at 2k rpm with white smoke coming from the exhaust. I dont know what to do. I cant have the car dying on me in the middle of traffic. So do any of you have any suggestions? Any help would be appreciated.

jcrome04

MAYBE the trunk wire harness???

cation

The first thing that I would do is plug up those vacuum lines going to the ACV on your P/S pump. Disconnect these vacuum lines where they attach to your intake and install rubber caps over the exposed vacuum nipples. These caps can be found at places like PepBoys and AutoZone.

I think that these lines may be your issue because you mentioned that one of them was broken and that you are getting white smoke. The white smoke could be power steering fluid being burned if it's getting sucked into your intake from the broken ACV via the one good vacuum line that I assume is still hooked up. Check your P/S fluid level to see if you are low. If you are, this is more than likely the problem and you'll either need to replace your ACV and vacuum lines, or just plug the ACV port in your P/S pump and go on your merry way.

If that doesn't solve your white smoke/stalling issue, you may have more of a serious problem.

Try what I mentioned above first and also check the trunk wire harness where it attaches to the hinge like jcrome04 said.

CAfast

i think so too. but the nipple broke off into the hose so im looking for a replacement for the hose instead of rigging something onto it. do you know anywhere or somebody that has the whole rubber intake piece with the junction? and possibly an idle air control valve? That maybe the problem too.

cation

The ACV along with the factory vacuum lines can be found online through an OEM parts dealer. The ACV is almost $100 and the vacuum hoses will be less than $20. IMHO, plugging the thing up is more economical. Good Luck man!