My 2007 yaris Idles rough when i come to a stop.

[phyrefighterjay]

2007 toyota yaris 300k miles! Because of the mileage I’m not looking for a miracle here obviously things are worn out. But I’ve been babying this car and it still has the original brakes! Recently I got a check engine light and replaced a couple coils… Number two and number four cylinder. The check engine light went away. I accelerated hard one time and the check engine light came back on. P0 300… P0302P0304. Same codes I was getting before before I changed the coils. The irony is after I did the hard acceleration the car actually started working pretty good. But the check engine light is still on and the engine runs just fine. With one exception. When I pull up to a stoplight after going 40 miles an hour… When the car stops...The engine has a hard time recovering back to idle speed… Just for about one second it runs really rough and then recovers back to idle. This only happens when the engine is in gear… If I started the car and let it idle in neutral it would idle with No misfire and no problems. This car could probably do for a fuel filter change… Obviously because it’s at 300 K… And I have fuel injectors on hand to replace The old ones. Is the transmission affecting my idol that’s why the vehicle has a hard time when it comes to a stop?

[Hiro]

I cant tell you what the rough idle is but I have seen that in several old vehicles with automatic transmissions, I have thought that the torque converter that transfers power from transmission to engine is why it goes away when in neutral or park but I have had trouble finding any solid info to back this up. I used to have a toyota previa that idled really bad and if i remember right it was worse when in drive with the brake on, after the shop did a thorough tune up it got better.

I also have a 2007 Yaris with nearly 300k miles, currently not running though. And I have had the misfire issue on 2 different cylinders, I think it was idling alright though when had it running last over a year ago. My mechanic told me it I could try and replace the coils but I didn't want to spend the money as they are so pricey.

[sh0rtlife]

i got a missfire a few weeks back and it was the crank position sensor..also an 07 but VERY low miles

i HAVE had that transmission based rough idle once...it was after 4 hours @70 on the freeway, and it sounded funny, i suspect the trans had locked itself in overdrive, it continued the next morning, after putting it into reverse it went away and has never come back

what i can tell you from other cars, honda and chrysler, is that when anything is directly connected to automatic in gear and idle that you should change the filter and fluid of the trans, if it perseists your looking for either a sensor issue or an IAC type of issue(idle air control) with the IAC issue being more common especialy on hondas

[IndestructibleYaris]

Clean throttle body, check battery, alternator, and all main power connections. I've heard this complaint a lot with the yaris and it's usually one of these things. What's more important to you is to fix the misfire. Most yaris doesnt have a misfire and idles low, yours must be horrible with a misfire