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Occasional rough idle

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Old 08-22-2024, 12:16 PM
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Occasional rough idle

Hey y’all

​​​​ so for the last couple months I’ve been having a rough pulsing idle from around 200-500 rpm. Sometimes it does it, sometimes it doesn’t. But there is situation where it becomes way worse and stalls. Off roading/rock crawling it seems to suddenly get very bad at random articulation and where the wheel is turned. And can happen on level ground with the wheel straight, but seems to happen more and more extreme on slopes/articulated randomly. I was getting a lean code and an o2 sensor code, changed the o2 sensor and both went away. Egr seems to open and close with vacuum, fuel pressure is good, doesn’t seem to be a vacuum leak anywhere, although I haven’t smoke tested it. Another thing though, the Rpm’s do rise around 100 while I press on the break. The break booster seems to be fine though. Super stumped here, any help would be appreciated.
-Teo
Old 08-23-2024, 11:00 AM
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Sounds like an intermittent vacuum leak to me. I just found one at my EGR-upper plenum seal.
I would smoke check the bay for vacuum leaks, especially near power steering lines and brake booster lines. There's an idle up that should occur when the wheel is fully turned and the power steering is pulling the most power. Also, that rpm is fairly low for idle but if you're crawling you may have it low intentionally.
Old 08-23-2024, 04:29 PM
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I’ll look into the vacuum system. I don’t have a smoke machine, if I try the carb cleaner with the engine cold you think that could do the trick?
Old 08-23-2024, 10:36 PM
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Here is what’s going on above. Sometimes it’s fine, sometimes not. Is it possible the fuel pump could not be able to suck enough fuel at random angles due to the slopes? Thanks
Old 08-24-2024, 09:47 AM
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i think that as long as the pickup in the tank is covered with fuel it will always be pumping fuel.

can't tell what vertical angle the vehicle is at, but the power steering whines when you turn, it's lugging the engine down because the idle-up that quicksilvah mentioned doesn't appear to be working??

i run hydro-assist with no idle-up function, when it loads up the 37's the 22re really struggles to keep running... this is a universal problem across all platforms, some people solve it with a hand throttle: https://www.pirate4x4.com/threads/id...wling.1027002/

we don't know what engine nor tire size you are running? there are general troubleshooting steps for checking power assist functionality for the brakes, and also for the egr, can't recall offhand... hold the brake pedal down while starting the car is one?

Old 08-24-2024, 10:07 AM
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I’m running 33s with a 3vze. The rpm’s do rise a very little amount when the pump is engaged, but I’ve had the stalling happen when the steering wheel is neutral as well. The hill is somewhat steep, with the left side being steeper than the right. It will idle low and pulse at random stop lights and sometimes be fine. Only does it below 750 rpm for the most part. I’ve had it occasionally misfiring on me too, but that really just happens wheeling after I start it back up from stalling.
Old 08-24-2024, 10:12 AM
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Dry steering never really has negative affects on my rpm. It will run some bad in situations, but if I want a guaranteed stall that hill always does it. Besides that it really only stalls wheeling.
Old 08-24-2024, 11:05 AM
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there was indeed a weird blip right at the end of your video, where the engine stalled(?), and it didn't seem to have anything to do with the wheels being turned?

testing the egr may not be relevant, but i'd do it anyway, look up the procedure in the fsm... as i recall on the 22re, you can suck on a vacuum port while the engine is running, to get a rough test of the egr: https://www.toyotanation.com/threads...please.329483/

that advice to check for vacuum leaks was also good idea, i'd be inclined to carefully examine all of the hoses... but neither of those things seems to be relevant to why it dies at an angle on the hill, that's rather bizarre.
Old 08-24-2024, 11:57 AM
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When vacuum is applied to the eye system, it kills the engine like it’s suppose to. But this got me thinking. Could the egr valve be getting unwanted vacuum causing the diaphragm to move? Don’t know why the hill would affect this, but just an idea.

Last edited by Teo Garofalo; 08-24-2024 at 01:08 PM.
Old 08-28-2024, 06:27 PM
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I just had something weird happen. I was putting the truck in that position and it stalled like normal. I left it like that with the keys in the on position for around 1 minute. Tried to start it and nothing. Now the truck will only start with a jump. What the hell is going on. How could that hill have fried something in my electrical system?
Old 08-29-2024, 08:01 AM
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sounds like the problem is getting worse... so when you tried to start it, the engine didn't turn over?

if you can repeat the failure try to troubleshoot it, per the fsm... at least it gives you something to work on.
Old 08-29-2024, 11:29 AM
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Almost seems like it shorted something. Battery has plenty of power, alternator changers, but starter will not engage unless I jump the car, which it starts immediately when jumped. I can drive the car after starting and it runs fine, but now right when I turn the car off it will immediately not start. No crank, starter isn’t engaging. When I left the truck on that hill for a minute or two I left the key in the on position allowing power to still circulate. It’s almost like the car might die at that angle because of a short, and since I left it there with the power on it fried something.
Old 08-29-2024, 11:30 AM
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Relays are good
Old 08-29-2024, 12:34 PM
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turn the headlights on, then try to start it, do they go dim? that would indicate that it's at least hitting the relay to the starter.

Old 08-29-2024, 08:05 PM
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I was about to look at the headlights, but figured I’d try it without a jump one more time. Started right up and now starts every time. Truck is being very strange. Wish this was easy to diagnose.
Old 09-10-2024, 12:24 PM
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FIXED. The no start was due to a dirty/ground terminal. For the idle, I decided to spray the engine with carb cleaner to look for vacuum leaks. Around the throttle body area, the rpm changed. I took of the hosing for the intake and boy did I find a big gash in the hose. Temporarily taped it up and runs like a dream. Fixed the low idle, pulsing idle, the hill, and I notice more power. I’ve had this intake hose off before but I somehow never noticed this. It used to always idle around 500 and I’m sure it was because of this hole, it just wasn’t big enough to stall the engine at the time. I’ll post a picture of the gash, glad to have finally figured it out.
Old 09-10-2024, 12:25 PM
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Old 09-10-2024, 12:30 PM
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those dirty grounds will get you every time! glad that it's fixed, probably get another hose on ebay
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