heddleston

I am having problems with the idle on me 99 4ruuner. The truck was my daily driver until last March when I bought a 2000 Honda VFR 800 motorcycle. Now I commute on the motorcycle and the truck sits unless I am going on a trip. The mileage is currently 127k. The problem started about two weeks ago when I was on a 6 hour drive to upstate NY. The idle was up around 1800-2000 anytime the clutch was pushed in. It kicked a CEL for the TPS. I stopped at autozone on the drive and swapped the TPS in the parking lot. This didn't change the idle issue but the original TPS does appear to be bad after a little testing with a meter. Once at my destination I put quite a bit of carb cleaner down the throttle body IAC hole...let it sit and started the truck. This might have helped some and the idle came down a little. Back at home in VA I ran a can of (can’t remember the kind) cleaning foam through the vacuum line in to the intake using engine vacuum. I also let this sit for a while and filled the IAC hole. This helped, the idle was reduced to about 1200 but some fluctuation in the idle once the clutch was pushed it. I also checked the vacuum with a guage...it showed 22. I decided that I had no other option but to pull the throttle body and IAC. This was very easy. I cleaned a lot out build up out of it and put it back together without replacing the black rubber gasket between the TB and the IAC. Once back together there was not a change in the idle, the 4runner acted the same. The idle is around 1100 all the time but if I am coming to a stop light and put in the clutch the idle will surge to about 1500 and then slowly come back down to 1100 where it settles. It doesn't seem to be tied to breaking but possibly seems a little worse if I am going faster. If I am at 45 and put in the clutch the idle might go to 1900 and then come back down. If I am at 15 miles per hour then it would surge to 1500 or so.

I am unsure of what to do. I might disassemble the IAC again and replace the gaskets, make sure I got everything back together correctly. I also plan to look at all vacuum lines again. I have sprayed everything with carb cleaner and nothing seems to be leaking.

Is there a way to set the TPS once it's installed? I can't find an install procedure in my service manual....just diagonistic information.

The CEL light is not on, I have reset the computer several times and I have cleaned the MAF. Anyone have any suggestions? I am going to work on the problem tomorrow.

heddleston

I am posting this in case anyone is researching for their problem. I took the 4runner to the Toyota dealer today, I finally decided to do the timing belt and water pump so I had them look at the idle problem also. It was a vacuum leak. Somehow the PCV vacuum line was not attached to the correct port. The problem I had started randomly, the hose must have slipped off or cracked so far as I can tell. I replaced some of the vacuum hoses with silicone lines to try and find the problem and when I did this I must have put them on incorrectly although I am still unsure how I did this as I did them one for one. I should have looked at the vacuum line diagram.