Hey All,

First off, let me say that this thread has saved my lots of $$ and given me good information to relay to my mechanic.

Here is the situation: 2000 4Runner 5 speed 4X4 has a weird idle problem. At times, the idle hangs around 1500 RPM when I am coasting to a stop and take the truck out of gear for those last few yards. What happens is that it will stay at 1400 ? 1500 after disengaging the clutch, then just before a full stop, it will idle down quickly to 850 or so (where it should be). I noticed that the problem got a lot worse after I towed my boat about 100 miles or so (got to around 1600 RPM when in neutral and wouldn?t drop below 1000 even when coming to a stop). It doesn?t happen all the time; the idle does come down smoothly at times.

We replaced the IAC, and CTS, and the throttle body is clean. Also, the O2 sensors and ERG seem to be OK (no error codes). Gas mileage is good (around 17 mpg city and highway) Truck was just tuned and has only 30K miles on it. It runs great, except for this problem. I don?t think it?s the dashpot either, and mechanic tells me it too would come up as an error code if it was shot. At this point, he doesn?t want to replace anything else without some sort of clue as to what is going on. The next suspect is the TPS. It is only about a $70.00 part, so I may just have him do it. One of the things I noticed is that sometimes, after I have driven it for a while, the idle will not come down past 1000 when in neutral at a full stop (not towing anything). It does sort of sound like the TPS, but I?m not sure.

I?ve read the posts here on idle problems, and most seem to be related to the IAC. I need to do the timing belt, so I may just do that TPS. Anything else I should check??

Thanks a lot.

 

I have a simular prob on my 2000 auto (wish i had your manual...). When i first start it it will idle at ~1500 rpm. I know this must not be good for it on a cold start. after i have been going for awhile it will idle at the correct speed.

 

this is normal. the engine revs high on a cold start so it will warm up faster. the tranny will also hold 2nd longer after a cold start to get the engine up to temp quicker in case you were worried about that too.

 

well that explaines it. Makes sense but just seems like that would be a no no with the oil not moving yet...

 

I have had the same issues on my manual and last week finally fixed it. Mine was actually the IAC. But in your case I would take that vaccume control throttle thing off of your throttle body because if the vaccum diaphram is bad it will hold the plunger out and cause your idle to stay high. This vaccum things job is when the engine reaches idle where the vaccum is at its highest, the valve shoots back and lets the car idle normally but if it is broke, then it will stick out. If you think it is the TPS then start your car and warm it up, then when the problem is happening, unplug the sensor and if the idle goes higher or your hear your engine make a different sound then the sensor is working. Try that...

 

Thanks 5-speed.

I have a feeling it is not the tps, so your suggestion will help us figure this out.

Thanks again.