Idle issues

I Recently purchased an '01 4x4 TRD Tacoma with a 3.4L 135k. I just noticed that is has some idle issues. It does not come back to idle speed very quickly.
It hangs up around 2000 or so for awhile when I depress the clutch, and then gradually comes back to the correct range. This happens at all running temps cold to warm.
Anybody have any ideas about what could be going wrong, or is this normal?

 

Have you noticed anything else happening? Anything at all -- i.e. Do you lose your heat (from the A/C vents) or does your exhaust smell sweet?

If it were me, and nothing else was out of whack I'd Seafoam the frigger.

 

It's not normal, and it's not clear evidence you need to Seafoam the engine.

Odds are it's a sensor or controller issue. I'd start with the idle air control valve.

 

+1


Flash

 

Totally agree. I was just suggesting that you try seafoaming if nothing else looks out of place...maybe that's not a logical step but that's what I might do, depending. I am far from an engine expert.

 

This happened with the 3.4 in my '97 4Runner. It was the Mass AirFlow Sensor. They are very fragile so don't touch it. There is cleaner specifically for this that you can buy at any parts store (Autozone, Pepboys, Checker, etc.) Once cleaned it idled perfectly.

 

I had some "sticky idle" issues for a bit after I cleaned my throttle body the first time. It turns out I should've just did it the right way by removing it since I ended up gumming up the idle air control a bit and had to remove it to clean that all up anyway. It would be idling around 1500 rpm and slowly drop to about 1000 rpm after about 10 sec.

Even though the FSM says the IAC isn't a serviceable part, I did remove it and cleaned it up good and everything was back to normal, idling around 650-750.

When I was having issues with my IAC, I was occasionally throwing a P0170 (I believe), then it eventually got to the point it was throwing a code that basically said the IAC was faulty when the temp started dropping a bit.

If it is the IAC, seafoam wont help as from what it looks like, the IAC is an electronic method to basically create a vacuum leak to increase the idle speed based on coolant temperature. 2k rpm seems awfully high for a stuck IAC though, so you might also want to check lines to make sure you dont have a vacuum leak somewhere. My truck does have an auto trans, so maybe with the trans fully disengaged (clutch in), 2k is possible with a sticky IAC.

There is an air hose that plugs into the IAC. If you disconnect that and plug it, your idle should be around 500ish or die all together. If it doesn't, its not going to be your IAC. Of course, as knayrb stated, there are quite a few issues related to the MAF which are easily fixed by just cleaning it. You may have to leave the battery unplugged for a little bit after wards for the computer to relearn sensor data.

 

Thanks for the tips! Hopefully one of them will work...