400rpm idle? Vibrating hard?

[Schamattack]

Got a weird issue. my 07 sr5 v6 with just a hair over 100k has a idle issue when on the brake. If my truck is in park it idles around 600rpm and feels smooth as day. Every other time I come to an intersection and stop with the brakes the truck drops to about 400-450rpm and vibrates, about 8 seconds later it jumps back to the 600rpm range and stops. Any ideas? No check engine lights. I replaced the air filter about a year ago.

 

[tay4R]

I was getting some similar low RPMs at a stop. I decided to use some Seafoam in the gas tank, crank case and intake manifold. I also cleaned my MAF and throttle body. Did that and reset the ECU and EFI fuses. Big difference since then. Better response and idle. Right after I cleaned everything, the idle was very high, but the computer just needs to re-learn for a bit.

 

[ZiaMan]

...I also cleaned my MAF and throttle body...

This right here!

 

[Schamattack]

I was getting some similar low RPMs at a stop. I decided to use some Seafoam in the gas tank, crank case and intake manifold. I also cleaned my MAF and throttle body. Did that and reset the ECU and EFI fuses. Big difference since then. Better response and idle. Right after I cleaned everything, the idle was very high, but the computer just needs to re-learn for a bit.

Going to do this over the weekend. Will post results.

 

[4RunnerIdiot]

I had a similar issue. Low idling, sometimes stalling, sometimes recovering. I was 2 quarts low on transmission fluid.

 

[fdbyrne]

I was getting some similar low RPMs at a stop. I decided to use some Seafoam in the gas tank, crank case and intake manifold. I also cleaned my MAF and throttle body. Did that and reset the ECU and EFI fuses. Big difference since then. Better response and idle. Right after I cleaned everything, the idle was very high, but the computer just needs to re-learn for a bit.

The problem with this approach is that you're doing too many things all at the same time. You won't be able to tell which of the things you did actually fixed the problem. Even worse, if something goes wrong you don't know what caused it.

I far prefer to make a list of likely suspects and hit them one at a time. First, reset the ECU since it's the easiest. Not fixed? Clean the MAF? Still not fixed? Keep going down the list.

 

[Johns06yota]

Got a weird issue. my 07 sr5 v6 with just a hair over 100k has a idle issue when on the brake. If my truck is in park it idles around 600rpm and feels smooth as day. Every other time I come to an intersection and stop with the brakes the truck drops to about 400-450rpm and vibrates, about 8 seconds later it jumps back to the 600rpm range and stops. Any ideas? No check engine lights. I replaced the air filter about a year ago.

Check the condition of the vacuum lines in the engine bay. after I replaced those a while back it fixed the exact same issue