Ok. I've done my research and searched through a ton of threads about this issue and have generally come up with a steady answer to my problem. Unfortunately, it does not seem to be working.
Basically, what is going on is that when my 92' SC400 is in park it idles up and down from about 1250-2000rpm. From my research I've found the general culprits to be the MAF, IACV (Idle Air Control Valve, for those who call it some other name), or a vacuum leak.
So far I have checked for vacuum leaks and found none, cleaned the MAF off with CRC, and removed the IACV and cleaned the plunger (which was all gunked up). Throttle cables aren't sticking either, b/c I did see that in one thread. Prob something I'd have overlooked.
Unhooked the battery to clean the MAF and tried starting it up. Fixed the problem for like 20 sec (wasn't looping, but was idling at 1100) and then when back to the idle looping. Same story with the IACV. Figuring that this 20 sec of "good" idling was just b/c the computer was getting reset by unhooking the battery.
Tentative plan is to take the whole throttle body of and clean it up. I have also heard that the TPS could be the issue. Not really sure what I should be looking for or adjusting here.
Any help on theories or suggestions are welcomed. I'll take pics of all the work I'm doing, for a write up on this issue later. Don't have a working multimeter though to check pins on MAF or IACV or anything though (but I believe there is already a write up on that)
Thanks,
Sean
Basically, what is going on is that when my 92' SC400 is in park it idles up and down from about 1250-2000rpm. From my research I've found the general culprits to be the MAF, IACV (Idle Air Control Valve, for those who call it some other name), or a vacuum leak.
So far I have checked for vacuum leaks and found none, cleaned the MAF off with CRC, and removed the IACV and cleaned the plunger (which was all gunked up). Throttle cables aren't sticking either, b/c I did see that in one thread. Prob something I'd have overlooked.
Unhooked the battery to clean the MAF and tried starting it up. Fixed the problem for like 20 sec (wasn't looping, but was idling at 1100) and then when back to the idle looping. Same story with the IACV. Figuring that this 20 sec of "good" idling was just b/c the computer was getting reset by unhooking the battery.
Tentative plan is to take the whole throttle body of and clean it up. I have also heard that the TPS could be the issue. Not really sure what I should be looking for or adjusting here.
Any help on theories or suggestions are welcomed. I'll take pics of all the work I'm doing, for a write up on this issue later. Don't have a working multimeter though to check pins on MAF or IACV or anything though (but I believe there is already a write up on that)
Thanks,
Sean
