osin

I had some problems lately with my 4Runner and got very suspicious on every new thing I hear or feel...

Just noticed this today when driving on the highway above 50-60 miles per hour. When I take my foot off from the gas pedal RPM's stay above 2000 but when driving with lower speeds, every time when RPM's are above 2000 and I take my foot off, they go as low as 1000.

So my question is: is it normal that on the last gear RPM's stay at the same position without pressing on the gas pedal?

If not, what can cause this?

It is 2000 4Runner 3.4L engine SR5 everything stock - 145,000 miles
I had spark plugs, wires, ignition coils and catalytic converter changed about 2000 miles ago...

RunningAround

Bad 02 sensor, or thermostat possibly. When you turn your heat or ac on is it working properly?

osin

O2 sensors were changed about 20,000 miles ago. Also car was recently 3 times at dealer's shop for misfire problem and cat converter replacement, so I believe they would check the sensors too...

AC seems to work fine, didn't check the heat though...I will try that today...

any other ideas?
it only happens with higher speeds...

RunningAround

No, sorry, I'm not a mechanic by any means. I have had those symptoms before in different vehicles and it came down to the 02 sensor or thermostat. Good luck!

Gerdo

When in doubt, disconnect the battery (negative cable) for a few minuits. This will reset the computer and takes care af alot of problems.

osin

I will try that tomorrow...

Just a little update.
I did about 6 different trips today and RPM's were going down to about 1500, even when driving 80MPH.
On the last trip problem returned. When driving above 50 MPH (on the last gear) RPMs didn't go down until pressing the brake. They were going down slowly with decreasing the speed...

Does anyone else have an idea what can be wrong?

Godzilla

My first thought would be your TPS.

osin

Should I wait for code?

Godzilla

I changed my TPS just for the hell of it a few months back. 50$ and 5min. It could be possible that the incidence is not occuring enough to actually flip the light, but just enough to begin driveability issues.

CTRJ

I was chasing this same problem over the last couple of months. My 4Runner would idle at 1500-1700 and would only go back to normal idle if I bliped the throttle to 4000.

After cleaning the throttle body and mass air flow sensor, my check engine light came on, indicating that my mass air flow sensor was bad. After replacing it, my engine idles at 750-1000.

I would start with trying to clean your MAF sensor. Be careful doing that, though, as you can damage it. I think that's what happened with mine.

osin

I'm sorry for not mentioning this before but I changed MAF sensor about 45000 miles ago (had code for this) and cleaned the throttle body about 10000 miles ago.

I've never seen TPS before. Is it possible to clean it like MAF sensor or it should be replaced?

Godzilla

Just replaced.

Fink

Just out of curiousity do you drive with overdrive on? what about ECT?

Fink

BigBallsMcFalls

and your point is ? MAFs need to be cleaned every 30,000. this is not the self cleaning hot wire model that newer cars have

osin

Both are off

I was switching both (overdrive, ECT) and also AC on and off, but no change.
Today I had this problem first drive at the morning but later was all good, opposite to what was happening yesterday...

I disconnected the battery, installed new air filter, filled the tank with different gasoline than before and problem is still there.

Will try to clean MAF sensor at the end of the week and possibly will change the TPS, unless somebody else will chime in with different idea...

Thank you all for posting...

osin

to be honest I didn't now that MAF sensor should be cleaned regularly...

osin

Just a little update for others who will find this thread in the future.

I've cleaned MAF sensor and throttle body but this didn't help...
Problem was coming back for couple of weeks and finally triggered the engine light - P0120 code => TPS - that is what Godzilla suggested

Sensor replaced and my 4Runner runs like new

Thanks guys for help...

DailyDrive

Are you saying that when going 80MPH and letting off the throttle with OD off, the engine RPMs only drop to 1500? And this "problem" went away now?

osin

The "problem" was that RPMs didn't go down at all. The fragment you quoted was to demonstrate that it wasn't happening all the time (on every trip)...

Hilux_3.0

I am Having the same problem, Just bought myself a 2000 T4R with 150,000 KM. Driving at highway speeds if I let off the gas the RPM is pegged at 1500 then as I start braking it follows the speed back down to Idle. Almost as If its trying to engine brake. I also notice it will down shift as I slow down.

I cleaned the MAF, TB, New mobile 1 ATF ( great stuff), Oil Change, Pulled the EFI fuse, Total reset of the ECU and still nothing. No codes have popped up yet.

Guessing TPS?