? about dropping rpm below normal when stopping

Kmvreter

Kmvreter

New member
Recently started to notice the following new symptom with my '04 V6 with 140,000 kms (~87K miles.) I do regular maintenance on schedule.

During a normal slowdown and coming to a full stop, the engine idle dips below 500 rpm for just a second and then recovers. I started noticing it because it feels like a hesitation (not quite a stalling) before it returns to a normal idle. This only happens with the engine warm because the cold idle setting is forcing a higher idle.

Any ideas as to what is going on?

Worst thing I'm thinking is it might be the torque converter clutch staying locked on too long. I'm going to test this out by downshifting into 2nd and forcing the TCC to disengage. What other engine items may cause this?
 
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Try manually downshifting. There's no scenario (IIRC) when the torque conveter will lock in 1st gear. If it you downshift to 1st at 15-20mph that should ensure the lock-up function is out of the picture.


Next just do some parking lot 0-15-0mph in 1st gear and see if it does it.


Mine is much newer than yours but I notice it occasionally too. My guess is it's some combo of temp and fuel formulation that the computer hasn't 'learned' yet. During the seasons when our temp varies I will get a day here and there where it does it a few times and then it won't do it for months.


Are you running in Defrost mode? Are your underhood temps getting just warm enough that the compressor is cutting on and off like summer time?


:cheers:
 
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CJ3Flyr said:
...
Are you running in Defrost mode?...
Click to expand...


Not using defrost, running auto temp for full heat these days.
I'll try some of your suggestions. It just started doing this because it isn't soemthing I've noticed before.
I'm going to look into what kind of EGR system is on this V6. Does it even have one?
I'm also thinking of checking the MAF sensor in the spring (where is the thread about cleaning it? Oh yeah, search sucks.)
 
Kmvreter said:
EGR system is on this V6. Does it even have one?
I'm also thinking of checking the MAF sensor in the spring (where is the thread about cleaning it? Oh yeah, search sucks.)
Click to expand...


I skimmed the emmissions section of the '03 FSM and saw no mention of an EGR. (That doesn't mean I didn't miss it:bash: )The MAF sensor is just left of front-center (right side of vehicle) when you lift the plastic cover. In fact there's a hole in my cover and you can see the plug/wires leading to through the hole.


This thread talks about cleaning MAF's and I used the Google trick to find it. Scroll down a bit and there's a pic with the location.


You are onto the Google search trick, right? Go to Google and type "MAF cleaning site:toyota-4runner.org" There's a sticky with Google tricks in Off Topic if you want to read more...

Off topic but I'm curious... Do you change oil etc based on your hour meter? You are one of a very few with an hour meter. My '99 Chevy had one, I loved it.


:cheers:
 
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Thanks for the info.

I do the maintenance based on mileage. The hour meter is more a curiousity just for recording purposes and calculations.
 
CJ3Flyr said:
I skimmed the emmissions section of the '03 FSM and saw no mention of an EGR...
Click to expand...

I also looked at various sections of the FSM and couldn't find anything about EGR on the V6.

I ruled out the TCC. The tranny is downshifting correctly.

I'll tackle some maintenance items that are coming due (when the weather changes) and include a look at the MAF.
 
The RPM drop and almost stallling after a hard stop usually indicates a Throttle Position (TPS) Sensor issue
 
JP4RNR said:
The RPM drop and almost stallling after a hard stop usually indicates a Throttle Position (TPS) Sensor issue
Click to expand...

It happens intermittently during normal stopping and is a slight hesitation. Thanks for the hint becuase now I'll try some hard stops, if and when it acts up, to see if I can make it worse. I'll also look at cleaning the throttle body.
 
coolant temp has a lot to do with engine performance

coolant temp has a lot to do with engine performance ...so I would say yes that the cold weather really has a lot to do with the way your engine starts and runs It has been really cold here i GA the last few weeks and my 4runner doesn't act the same starting and running as when its warm weather here
Dwayne
 
Re: Re: x2

Kmvreter said:
... BTW, I'm wondering if this intermittent is weather related. It's warmer now than the deep freeze we had earlier and I can't repeat the issue.
Click to expand...

I'm thinking there is a definite temperature link to this issue. It's colder now and the issue has returned. I'll wait for better weather to check some of the items pointed out earlier.
 
Here's an update.

I didn't do anything with the TPS or MAF on purpose to see if just the tuneup with new plugs and air filter helps. The truck now idles slightly higher at startup (breathes easier.) We had a cold snap last night and I noticed the problem is resolved. The idle doesn't drop to the annoying low hesitation level. I'll keep this in mind and use it as a future indicator for service of the air filter.
 
Thanks for the update....always good to here updates and issue resolved!

I have a sister who lives in Wasaga Beach and I know by her stories she tells... it gets really cold there in winter and causes a lot of problems with autos....LOL

good luck and keep updating
 
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