Rough idle at stop

C_GANSON

MEMBER
2003 TOYOTA TACOMA
2.7L
4 CYL
2WD
AUTOMATIC
160,000 MILES

Hi, when I go to a stoplight (still in drive) my truck rattles/rough idles for only about 5 seconds and then goes back down from 1, 000 RPMs to 600 RPMs 600 being resting idle.

I’ve replaced the spark plugs, battery, air filter,
Etc but nothing seems to work. Before replacing the spark plugs, this rough idle lasted for about 20 seconds while at a stop but is now at about 5.

Tuesday, April 27th, 2021 AT 12:44 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi,

The first thing that comes to mind with a rough idle, is a vacuum leak. However, a vacuum leak won't fix itself. That leads me to the EGR valve. I'm questioning if it has a lot of carbon and is sticking.

Let's try this first. Check to see if there are any engine vacuum leaks. Here is a link that shows how that is done:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

If you find no problems, then I would suggest removing the EGR valve and checking it and where it mounts on the intake to see if there is excessive carbon that could prevent the valve from properly working.

I attached a pic of the EGR location. It was the best I could find Let me know if you locate it.

Let me know.

Take care,

Joe

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