99 Acura TL

#1 searched but didnt find anything specific about the temp gauge being stuck. it stays halfway all the time with the car on or off, never moves basically.

#2 i was having idle bouncing issues previously so i changed the idle control valve and fixed it from bouncing but now every once in a while while in park the car revs back and fourth constantly between 1.0-2.0 rpms pretty quick like if i was reving it but goes up and down constantly.

any suggestions are very much appreciated.

 

1= it never goes down when car off? test the temp sending unit on engine
It should always run 1-2 lines below half,,but drop to nothing when cold
should also warm up within a few minutes to half and stay
if it moves wildly you have a real problem

2= when you replaced iacv what was included?
did you clean the chamber where iacv rod fits- it gets gummed up and iac rod wont rotate,,
most of us can get by with a good cleaning of iacv rods air slit and chamber, usually when cleaning intake manifold egr passages

 

Have your cooling system pressure checked for leaks. Trapped air pockets can cause the idle to fluctuate as it fakes out the sensor and valve. Also make sure that the coolant ratio is correct. If the system is airtight, then check the ECT sensor or temp sending unit......and lastly the guage itself may be inoperative.

 

I took out the idle control value again just to make sure everything was good, the little coolant passage was a little gunked up, I did degrease all three passages last time, other than the coolant one clean as a whistle. I also get a bit of a rev when I come to a complete stop like goes to 1.5 and idles back down.

Where's the ect? What's that do

 

The engine coolant temperature (ECT) sensor reads the temp
and determines the value for the computer to adjust the idle speed upon cold start-up.

 

Another thing i noticed yesterday which is very weird, the car stays accelerated after i let go of the pedal. I can stay crusing at the same speed without even touching the pedal, instead of slowing down by itself like a car should.

 

That's not good at all. Try to lube the throttle cables for that.

 

Yeah, that may cause ya bigger problems if it decides to stick at the wrong time and place.
Check out all recent work and do as Mil Dave suggested, asap !

 

These crazy cars, drive to the gym today and temp dropped here in Florida and car drove fantastic no idle issues at all. Leave the gym and starts doing it again, so I'm thinking you might just be right about the ect..

 

So changed the ECT out and still having the same issue, when in park idle bounces for a little than stays stuck on 1.5-1.9 and while coming to a complete stop idle bounces up once and than back to normal while in drive. any other suggestions?? seems like it only happens when the car is up to temperature cause runs very smooth the first couple mins of a fresh start.

 

You may have a slight air leak leaning out the engine.
Check the IAC valve (Idle air control)
See the you tube vid to see if it is similar to your issue.

 

A sticking throttle plate from a gunked up throttle body can cause this too. Get carb cleaner, spray it in the TB and plate and clean them really well. Then lightly lube the 2 hinges of the throttle plate inside the TB.

 

Cleaned it twice actually, first time and second time i took everything back apart to make sure everything was on correctly. i just replaced the Idle Control valve with a new one but still end up with the same idle issue. Anything i'm missing or something i should be cleaning?? also from reading on other threads, what rod is what gets gunked up cause the only rod i've seen is inside the actual idle control valve and its clean as a whistle??

 

Perhps there is an air pocket trapped within the cooling system, try bleeding it.

 

Let it run for a couple mins with radiator cap off and heater running so pretty sure its bleed. Noticed its only happening when the car is at operating temperature, runs perfectly smooth before than, than once up to temp, the idle bounces in parking only, get a little rev at a complete stop, and get a really bad shake between 40-45 mph. Also whenever hitting and letting go of the gas the engine seems rougher as if an engine mount was broken on both release and accel but doesnt do it before warm up and shifts smoothlym tranny shifts great except when that shake happens and was recently rebuilt. A little stumped on what it could be....

 

So far i've changed the IACV,the ECT, and burped the radiator twice but still having the same idle issue, seems to happen more when the car has been run for a little.

 

Today I pulled everything apart including the intake manifold, lets just say that EGR port looked like someone stuck a piece of gum on it and it dried it closed. Stuck a screwdriver through it and cleared it out. Left the whole intake soaking to get a lot of the gunk off, was pretty dirty, went ahead and changed the thermostat as well while I had the chance. So hopefully this idle crap goes away...

 

I m having the same problem as the video heres what Ive done
Car was fine but I put in new Iridium plugs and valve cover & plug seals.
A month later I had Random multiple misfires. I couldn't find why. I did a valve adjustment and cleaned the intake manifold and the throttle body.
Now I had misfires and when car was at idle in P/N it would bounce about 1000 to 2000 RPM sometimes a little higher.
I fixed the misfires it was one bad coil!!!!!
Now I still had the idle problem, So I Checked for vacuum leaks using carb cleaner....nothing. I cleaned the throttle again really good and also cleaned the IACV. Bled the cooling system. Reset the PCM after every attempt and nothing!!!! The TCS light is also on.

 

Ever figure out what was causing the idle issue??