V6 Won't Idle

[Adumb]

I've been having this issue with my truck this winter where from time to time it'll start but it wont want to idle. It got bad enough on Saturday that I needed a tow.

When it's acting up, the truck will start and rev up to 1500 rpm or so, then when it goes to settle back to idle, it'll stall out. Sometimes I can keep it running by pumping the gas pedal and revving it around 2k rpm or so, but then when I let off the pedal it comes to idle, gets rough, and stalls. On Saturday for the first time it started stalling while I was driving.

It has done this both engine warm and cold. I've also had a drop in mpg's so I assume I'm running rich.

I am curious what runs the idle on our trucks since I don't see an idle air control valve.

I haven't been having the CEL come on. I'll check for codes in the AM though.

Any help would be greatly appreciated!!

 

[gm350reratliff]

Try removing the throttle body and give it a thorough cleaning. I would also suggest cleaning the MAF sensor. Is the check engine light on? Scan for codes.

 

[awdjunkies]

Try removing the throttle body and give it a thorough cleaning. I would also suggest cleaning the MAF sensor. Is the check engine light on? Scan for codes.

Also, to add to this^ when was the last time the plugs were replaced?

 

[BlackWorksInc]

As was stated above perform the following:

• Clean the throttle body
• Clean the MAF sensor
• Replace the spark plugs if they have not been serviced in the last 30k (service interval for standard copper plugs the 4th Gen 1GR-FE engines use)
• Disconnect the battery for 5-10 minutes
• After reconnecting the battery let the vehicle idle for about 5 minutes with no loads on (i.e. no headlights, no radio, no HVAC on, ect.)

The above steps should help the engine run a bit better; the final steps relearn the vehicle idle.

 

[Adumb]

Also, to add to this^ when was the last time the plugs were replaced?

Plugs were replaced with iridiums about 10k ago.

As was stated above perform the following:

• Clean the throttle body
• Clean the MAF sensor
• Replace the spark plugs if they have not been serviced in the last 30k (service interval for standard copper plugs the 4th Gen 1GR-FE engines use)
• Disconnect the battery for 5-10 minutes
• After reconnecting the battery let the vehicle idle for about 5 minutes with no loads on (i.e. no headlights, no radio, no HVAC on, ect.)

The above steps should help the engine run a bit better; the final steps relearn the vehicle idle.

Will give this a go this afternoon. Do I clean the Throttle with the MAF cleaner?

 

[BlackWorksInc]

You could I suppose? MAF cleaner typically isn't that strong and isn't really meant for cutting carbon deposits though (its more meant to clean sensitive sensor filaments.)

So it wouldn't hurt to get a can of carbon cleaner or throttle body cleaner (it tends to vaporize a bit better as well).

Also whatever you do, do NOT manipulate the throttle blade with the key on. Always do so with the key off (even better, just disconnect the battery, do your MAF & TB cleaning and reconnect it when you're done! )

 

[earthrealm]

As was stated above perform the following:

• Clean the throttle body
• Clean the MAF sensor
• Replace the spark plugs if they have not been serviced in the last 30k (service interval for standard copper plugs the 4th Gen 1GR-FE engines use)
• Disconnect the battery for 5-10 minutes
• After reconnecting the battery let the vehicle idle for about 5 minutes with no loads on (i.e. no headlights, no radio, no HVAC on, ect.)

The above steps should help the engine run a bit better; the final steps relearn the vehicle idle.

had same problems on my rav4 years ago...these exact steps solved the problem!...especially cleaning THE MAF and TB

 

[97hb]

All the idling is done with the tb. Mine is at 16-17ish % idling at steady 700rpm. Obd2 port will tell you if tb % is off. Almost all dbw vehicles use the tb to idle.

 

[97hb]

Also timing while idling is a rock steady 15 degrees. Spec is 15 + - .5

 

[Adumb]

You could I suppose? MAF cleaner typically isn't that strong and isn't really meant for cutting carbon deposits though (its more meant to clean sensitive sensor filaments.)

So it wouldn't hurt to get a can of carbon cleaner or throttle body cleaner (it tends to vaporize a bit better as well).

Also whatever you do, do NOT manipulate the throttle blade with the key on. Always do so with the key off (even better, just disconnect the battery, do your MAF & TB cleaning and reconnect it when you're done! )

Alright, about to head out into the cold and do this. thanks for all the help BlackWorks!

had same problems on my rav4 years ago...these exact steps solved the problem!...especially cleaning THE MAF and TB

Alright, glad to hear! I'm hoping it works for me too.

All the idling is done with the tb. Mine is at 16-17ish % idling at steady 700rpm. Obd2 port will tell you if tb % is off. Almost all dbw vehicles use the tb to idle.

That's what I was thinking would control the idle since with the dbw the vehicle can manipulate the throttle itself instead of needing a separate valve.

 

[Adumb]

I got a laundry list before I disconnected the battery.

P0038
P0058
P0121
P0123
P0450
P0453
P0607
P2103
P2135

Some of these seem to be related to high/low voltage which could be from the engine stalling. There are quite a few TB codes. Some say dirty TB, and some say faulty. The P0607 is kind of a scary one, but the positive terminal was pretty corroded when I went to remove it.

All I can think is how much easier a bad throttle cable is to diagnose and how much cheaper it would be to replace. :noidea:

 

[BlackWorksInc]

Have the battery and alternator tested.

 

[Adumb]

Have the battery and alternator tested.

Just finished up with the cleaning. The TB was pretty dirty. I unbolted it from the intake to get a more thorough cleaning.

I'll start it up and let it run now to relearn the idle, and I will drive it down to AZ to get the battery tested.

Thanks again BlackWorks.

 

[Adumb]

After Idling I got 2 EVAP codes and and random multiple cylinder misfire. I cleared them and only the EVAP codes came back. I'm guessing the misfire code was from the truck relearning its idle.

The battery checked out as good. The alternator I should take off and take in to get tested, right? I think I remember AZ having an on vehicle tester when I worked there but I also don't remember it being very accurate.

 

[fullboogie]

Depending upon which evap codes you got, it may be your gas cap. I just had this happen last week, so I replaced the gas cap with a genuine Toyota one and the codes are gone. Might keep your eye out for this.

As far as misfires, I get tons of those too. New plugs, truck runs great, but misfires are always present. Not sure I'd worry about that if all else is running OK.

 

[Adumb]

Sounds good, thanks Boogie.

The truck has been having these idle issues at about one week intervals so it'll be tough to determine for a bit if I have fixed anything today or not. I will keep you guys updated though.

I have my fingers crossed and I will pray to Odin for his mercy.

Again my gas mileage was down. I think it was down to 11 or 12 MPG, so if that improves it will be a good indication that I might have done some good.

 

[BlackWorksInc]

After Idling I got 2 EVAP codes and and random multiple cylinder misfire. I cleared them and only the EVAP codes came back. I'm guessing the misfire code was from the truck relearning its idle.

The battery checked out as good. The alternator I should take off and take in to get tested, right? I think I remember AZ having an on vehicle tester when I worked there but I also don't remember it being very accurate.

I'd put a DVOM on there and see what the voltage reading is. If its about 13~14v I wouldn't worry to much about it. Just clean the terminals and battery top really good with an acid reducer.

 

[Adumb]

I'd put a DVOM on there and see what the voltage reading is. If its about 13~14v I wouldn't worry to much about it. Just clean the terminals and battery top really good with an acid reducer.

I tried to use my battery cleaner and terminal sealer earlier but the aerosol cans were frozen lol.

Have you ever seen any throttle go bad on the v6? With all the codes my gut is leaning towards that but I don't want to replace a good one for sure.

 

[drewm]

Plugs were replaced with iridiums about 10k ago.

What plug exactly? Are you sure you didn't get the wrong plug? The V6 and V8 run different plugs. The wrong plug will do exactly this.

 

[BlackWorksInc]

I tried to use my battery cleaner and terminal sealer earlier but the aerosol cans were frozen lol.

Have you ever seen any throttle go bad on the v6? With all the codes my gut is leaning towards that but I don't want to replace a good one for sure.

Drive it for a bit and see if DTCs come back before we start condemning anything of that nature. They don't often go bad, but it is not out of the realm of possibility.