rcdemon1

anyone having a problem with rough idle. started at 10,000 miles toyota says there is nothing wrong because the computer is not coming up with anything . even though they can see the motor shaking.

mnscionxb

mine will but only for a sec or so every now and then might just be be cheep gas.

formare

Mine just started idling rough - around 20K taking it in tomorrow.

coryjames

is it when the ac is on this is common i have a solid motor mount well closse to so it gets a little rough at idle when the ac was on

rcdemon1

no i used injector cleaner,that stopped it.the motor mount is another story.i have the same vibration that you are talking about.the motor mount took a while to brake in.it used to cause viberation all the time. now its only a little in first gear and when the a/c is on........frank

XD40tC

I like it rough...

Tenfeathers

This may not fix all rough idle's but it sure fixed 3 cars here in town.
Get you a can of Seafoam fuel additive and only this brand pour the whole can in at a 1/4 tank drive it about 30 miles then fill it up and it will be smooth as can be.
just our exper.
There seems to be a build up of gunk and carbon in the fuel system and this stuff rocks.

ScionFred

iTrader: (1)

Cleaning the MAF every 20K miles couldn't hurt.

JoeSpeed

I used 89 octane gas and I no longer have that problem. I used to buy the cheap gas and then put some Oct Booster, or a Gas additive to keep it smooth. But I found that if I buy better gas it's just that same... However, I still put in gas additives once in a while to keep the injectors clean.
I hope this helps!

mnscionxb

I just change spark plugs at 47000 thay looked beat up switched to ngk

pyroman131

Apparently this is a very, very common problem with Scions. I've brought my box to the dealership at least 3 times. The a/c runs extremely rough as hell, and even when idling without, it runs rough.

I'm clueless as to what to do. I think the next time I fill up, I might go up to 89 octane. I use Shell 87 and I heard that adding Plus or Premium has no effect on this car.

draxcaliber

my engine would occasionally idle rough with the supercharger and weapon-r header, but it was usually followed closely by a code for not having a cat, and as soon as i cleared it with my scangauge, the car went back to normal. really weird since that isn't a code that would effect that. always happened, only once each spring.

have you tried resetting the ECU so it trys to relearn everything to idle better?

jnaval

I always check my engine and it doesn't seem to idle rough as it is described in this thread.

AAG

iTrader: (1)

Run a bottle of Redline fuel injector cleaner. Its suppose to work extremely well and the effects last longer than other injector cleaners.

RC-PILOT

# 1 cause is dirty injectors. SEAFOAM, REDLINE, BG PRODUCTS..... these all work.

PLEASE stay away from fuel additives other than these. The reason these other additives like OCTANE BOOSTER and others will actually add to the problem over time. They can also cause problems with your O2 sensors. These additives were designed to help older cars deal with newer fuel blends.

If you have no codes and a rough idle.....clean the injectors. Trust me on this one.

pyroman131

How do I go about resetting the ECU? I'm going to try that route first. If that doesn't work, fuel injector cleaner. I'll be going with Redline, as per suggestion. After, I'm going to try the 89 gas.

What happens if I put 89 or 93 gas into my car? I use Shell 87 (Regular) because I heard there's no benefit with higher gas grades. Plus there is a rumor (hopefully you guys will dismiss this) that stronger fuels are actually detrimental to our cars over time??

TheCCBox

iTrader: (1)

I put high grade in to do the cleaning for me and it makes it run great. I do it like it once a month cause of the price. But other then that it runs great! I also use seafoam every once and a while always helps clean to LOL!!!

pyroman131

So what is everyone's recommendations? A stronger fuel or should I learn towards some additives to help clean the fuel injectors?

What about the MAF sensor or O2 sensors or whatever? Sorry, I'm pretty intermediate when it comes to cars, but nothing way too over my head.

jnaval

IMHO, I think you're good with just cleaning the injectors and other sensors, try that first before getting yourself into a tub of chemicals. If that works, then that was the problem and that's all you needed. The other steps will be unnecessary. But if the problem persists, then that's when you take the other steps.

TrevorS

iTrader: (1)

Whenever the engine is running, the ECU continues to monitor the sensors and adjust operating parameters. So, unless something was just changed, resetting the ECU should have no useful affect. Seafoam or equivalent in the tank sounds like a much more likely solution (ie. dirty injectors).