Stalling with high outdoor temps and slow speed

[shamrock94]

Did a search but could not find this specific problem mentioned so any suggestions would be greatly appreciated. Working in the Mojave Desert with temps in the 110 to 120 range. My 1996 4Runner does fairly well at these temps except when I am forced to escort work vehicles at less than 10mph. Then it starts stalling repeatedly and will also stall when idling. I can put the truck in neutral while stalled and start it right back up. If I give it a break and start driving it over 10mph again it will drive with no issues. Had a mechanic check it out when it was doing this a couple of years ago but I live in a much cooler area and they could not get the problem to repeat.

Today I tried unplugging the MAF sensor thinking it was a fuel/air issue and the truck ran less smoothly but instead of stalling like it usually would at low speed it would hicup a little bit and the rpm would jump and the engine kept running. No error codes associated with this issue until I unplugged the sensor today.

So is this a faulty MAF sensor or is it something else that the sensor impacts?

Thanks!

 

[JZiggy]

Fan clutch?

 

[StreetCreeper]

Did a search but could not find this specific problem mentioned so any suggestions would be greatly appreciated. Working in the Mojave Desert with temps in the 110 to 120 range. My 1996 4Runner does fairly well at these temps except when I am forced to escort work vehicles at less than 10mph. Then it starts stalling repeatedly and will also stall when idling. I can put the truck in neutral while stalled and start it right back up. If I give it a break and start driving it over 10mph again it will drive with no issues. Had a mechanic check it out when it was doing this a couple of years ago but I live in a much cooler area and they could not get the problem to repeat.

Today I tried unplugging the MAF sensor thinking it was a fuel/air issue and the truck ran less smoothly but instead of stalling like it usually would at low speed it would hicup a little bit and the rpm would jump and the engine kept running. No error codes associated with this issue until I unplugged the sensor today.

So is this a faulty MAF sensor or is it something else that the sensor impacts?

Thanks!

My truck will do similar sometimes in extreme heat situations where I’m either moving slowly or idling a lot. It doesn’t happen too often but once or twice a year when it’s 107+. I researched it a long time ago and seem to recall the general consensus was it was IAC related or something. I decided it doesn’t happen enough to bother me and even when it did, restarting the truck and moving a little faster always seemed to take care of it quickly. So I never pursued a fix.

You really ought to get a OBD2 scanner and watch your actual coolant temps to see if you have a cooling issue when this occurs (the dash gauge is mostly useless). As JZiggy mentioned above, your fan clutch could be failing you and this is just the first symptoms of a clutch on its way out.

In your environment with those temps, I would be monitoring the coolant temps religiously. Outside of accidents and lack of oil changes, nothing seems to kill motors and tranny’s more than excessive heat — even hard to kill 4runners.

 

[shamrock94]

Thanks for the responses. I will get an OBD2 and monitor the temp. The gauge reads solidly in the same spot regardless of driving speed or outside temp but could be a possibility.

 

[theriddler]

Has it been worked on lately or have you changed anything? I put some Bosch +4 plugs on a Tacoma one time and it lost mpg's, power, and i even had some misfires. I was young and stupid...expensive lesson learned there. Give it a tuneup if it's been a while since it's had one, that's where i would start

 

[shamrock94]

Had the plugs and wires changed this winter. Also had a mechanically inclined coworker check out the fan clutch and he said it seems to be working normally. It is trying to stall more often the higher I am running the AC fan. Though I can keep it from stalling if I run it in a lower gear at higher RPM. It still tries to stall but with the higher RPM it jumps back up before it dies.

 

[heat]

Shades of a dying alternator...

 

[19963.4lsr5]

I would clean your IAC or while its idling shoot small squirts of carb cleaner into the air bypass hole of the IAC and let it suck the crud into the engine to burn.

I say short squirts because it will want to stall from ingesting the carb cleaner. If this is effective you will notice a higher idle and it will need to remap its idle control.

Edit: I used both sensor safe throttle body cleaner and regular carb cleaner to do this.




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