2009 4 cylinder 5 speed, rough idle and stalling

Today, I suddenly started having a problem with my Tacoma. It is a 2009 4 cylinder with 5 speed. It was kind of hard starting and has a low idle speed of about 500rpm or less and really rough. If I give it gas, runs smooth no problems. Ran great on the highway and city streets on my way home until I get to an intersection. Most times it stalls out and if it doesn't it idles really low. There is no Check Engine light on or anything else indicating a problem.

It ran fine yesterday when I was out, the only thing I am wondering about is I had my battery disconnected while changing out my 7 pin trailer connector yesterday afternoon. I can't see this having any bearing on it but just wanted to mention it.

Anybody have any suggestions?

Thanks.

 

Same thing happened on my stepdaughters Camry last week when i disconnected the battery. Take the intake hose off the throttle body and clean the carbon build up from the inside. When you disconnected the battery the ECU went back to factory setting for the position of the flap inside the TB and is no longer compensating for the build up of carbon. Take a rag and soak it in carb cleaner and wipe out that carbon as best you can. I didnt get it completely clean and it still worked.

 

Throttle body clean could very well help. We see cars with low, rough idle come in and this service seems to help clear it up. Usually the same thing. Only at idle when the butterfly is closed and the build up can make the most difference.

 

Good points by all above. Also, your engine may be experiencing an influx of air not being read by the mass air flow sensor. Ensure intake tube clamps are all tight, no physical damage to the tube and note any potential vacuum leaks.

 

All this, and sometimes just let it idle for a while so the computer can relearn and adjust.