97 4Runner Stalling at idle.

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mercuryrising17

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So I just had my timing belt changed, I had no power while driving and after a month of troubleshooting with new plugs wires cleaning MAF etc we found out the timing gear had worn out and the timing slipped. It has been running great for two weeks but all of a sudden today while coming to a stop it just stalled out. Fired right back up though. After an hour I got back in and started driving around town and everytime I would come to a complete stop the RPMs would jump and then it would stall. I plugged in my diagnostic tester and I am getting multiple misfires. While sitting in my driveway, I noticed that if i turn everything off, fan, radio, lights then it will stay running. however if i crank on the fan and radio and tap my break it will shut off again.
I am leaning towards it being a battery that is weak and not supplying enough voltage to keep the truck running, hence when I turn everything off it will stay running and when Im drawing amps from the battery it will stall. I believe that because it runs fine while driving at normal speeds that the alternator is fine, but it doesnt have enough power while idling to keep everything on.
Any thoughts or similar experiences? Ive never had a battery start to die on me, its always just been dead one day. Im also wondering if i should take it back to the shop to see if they missed anything, but Im seriously doubting that. It has run better then ever for me since i bought it 8 months ago since they fixed the timing, Im even getting great MPG now.

Thanks in advance guys!
 
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mercuryrising17 said:
So I just had my timing belt changed, I had no power while driving and after a month of troubleshooting with new plugs wires cleaning MAF etc we found out the timing gear had worn out and the timing slipped. It has been running great for two weeks but all of a sudden today while coming to a stop it just stalled out. Fired right back up though. After an hour I got back in and started driving around town and everytime I would come to a complete stop the RPMs would jump and then it would stall. I plugged in my diagnostic tester and I am getting multiple misfires. While sitting in my driveway, I noticed that if i turn everything off, fan, radio, lights then it will stay running. however if i crank on the fan and radio and tap my break it will shut off again.
I am leaning towards it being a battery that is weak and not supplying enough voltage to keep the truck running, hence when I turn everything off it will stay running and when Im drawing amps from the battery it will stall. I believe that because it runs fine while driving at normal speeds that the alternator is fine, but it doesnt have enough power while idling to keep everything on.
Any thoughts or similar experiences? Ive never had a battery start to die on me, its always just been dead one day. Im also wondering if i should take it back to the shop to see if they missed anything, but Im seriously doubting that. It has run better then ever for me since i bought it 8 months ago since they fixed the timing, Im even getting great MPG now.

Thanks in advance guys!
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Check/test the alternator to see if putting out enough voltage, as well as battery.


Also, it might be the IAC valve on throttle body. You should clean it out well, there are threads showing how to do it.
 
Thanks,
I just got back from the parts store and they tested the battery, it showed good. The alternator is only showing 12v at idle, isnt that real low? I was thinking it was supposed to stay at around 14v at all times? Just want to make sure before i spend the money on a new one.
 
Ok scratch that last post. I just put a multi meter on it myself and here is what I found. Pre start up the battery is showing 12.11 volts which is normal. at idle with no accessories on i have 14.13 volts. when i turn on the radio and lights it dips between 14 and 14.11. Then when I turn on my fan the the rpms jump and as it is dying it goes to 13.2 volts. Not sure if it is dipping because of the rpms bouncing around or it is really just an alternator starting to go out but has just enough life to power without a load. Any thoughts guys? The really weird part is that it runs fine if i keep some gas on it and i have just cleaned all the MAF and TB while i was figuring out my last issue. Has anyone ever heard of a bad alternator with these symptoms?
 
Check for vacuum leaks, they often show themselves at idle and can stall the engine.

<iframe width="560" height="315" src="https://www.youtube.com/embed/9CPqbaSgcok" frameborder="0" allowfullscreen></iframe>

If that's not it, check and clean the Idle Air Control Valve under the throttle body. You might have bumped it or dropped some sediment into the valve and blocked it up when cleaning.
 
Electronics shouldn't but some systems use VCV (vacuum control valves) that might mess with it. It's very easy to check and should only take you 1-2 minutes tops and will completely rule it out.

You might even find a leak, repair it and find your 4Runner runs better than before! Not the first time that's happened to one of my cars.
 
Awesome, thanks again man. Just checking for all the possibilities while im at work before i go out and get the stuff to start testing in a bit. I appreciate the response!
 
Wouldn't a vacuum leak also throw an engine code and turn on the CEL?

I haven't had my 4runner for long, but on the other cars I've owned even a minor vacuum leak that doesn't cause any noticeable symptoms would turn on the CEL.
 
WallyWest said:
Wouldn't a vacuum leak also throw an engine code and turn on the CEL?

I haven't had my 4runner for long, but on the other cars I've owned even a minor vacuum leak that doesn't cause any noticeable symptoms would turn on the CEL.
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It seems for these 4Runners, it only throws it if it's in the air intake. Anything else (PCV, brake booster etc.) it won't.
 
Well, I just got done cleaning the IAC which needed done regardless, and checking for vacum leaks. Neither of them worked and i dont think its a bad IAC valve because when I am turning on accessories the RPM's do rise like they are supposed to right before it stalls.
Im probably going to buy an altenator tomorrow and see if that helps and if not ill just take it back to autozone for a refund. Real weird problem, has anyone ever seen an alternator do this? Seems like it just cant quite put out enough power at low 600 rpms to run everything.
 
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gamefreakgc said:
It seems for these 4Runners, it only throws it if it's in the air intake. Anything else (PCV, brake booster etc.) it won't.
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I had a hairline crack on my charcoal evap emissions can that was causing a CEL. What I have learned is the smallest vacuum leak will eventually cause a CEL.
 
Tried a new battery and a new alternator today, and neither of them worked. Really starting to scratch my head on this. Could it really be a bad IAC valve and still cause every cylinder to misfire? If so is there a good way to check the IAC for proper funtioning? It seems to work fine, When i turn my AC on the rpms rise to 1000 and it idles at 1300 during warm up. Is there anything they could have done while changing the timing belt that could cause this, I doubt it because it has ran great for 2 weeks but you never know. Any ideas would help. Thanks guys.
 
mercuryrising17 said:
Tried a new battery and a new alternator today, and neither of them worked. Really starting to scratch my head on this. Could it really be a bad IAC valve and still cause every cylinder to misfire? If so is there a good way to check the IAC for proper funtioning? It seems to work fine, When i turn my AC on the rpms rise to 1000 and it idles at 1300 during warm up. Is there anything they could have done while changing the timing belt that could cause this, I doubt it because it has ran great for 2 weeks but you never know. Any ideas would help. Thanks guys.
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Did they replace the tensioner?
Pull the top cover off the timing belt and check. You never know.
Did you remove the IAC from the throttle body or just remove the throttle body from the vehicle?
Try running seafoam through a tank of premium fuel to see if it clears up. Could be a plugged injector
 
They didn't replace the tensioner, the timing belt had been changed 20k ago before I bought it and whoever did it didn't torque down the main gear, that wore out and caused the slip. Only new parts were the gear and the belt. I ran sea foam through just prior to the timing belt being changed two weeks ago as I was diagnosing. I didn't remove the iac because one screw was starting to strip out but ran an entire can of carb cleaner through the opening and it was coming out clear. The gate was moving very freely, maybe it is an intermittent iac? I'm going to test again in the morning for vacuum leaks, maybe I just missed one.
 
Sometimes the IAC is clogged in the coolant passage, not the actual sensor. So you might want to try and take it off, up to you though. If it's clogged in the coolant passage though, you'd also notice crud in every other coolant passage on your engine.

We kinda passed up the basics here. Any check engine light codes and if yes, which ones? Spark plug wires are in the correct order? Have you tested your coil pack with a multimeter?

Sometimes the Throttle Position Sensor will cause funny issues, but will usually also throw a code.
 
I'm throwing a p0300 code. Every cylinder is misfiring. But this isn't all the time, after clearing the codes it takes a while to get back on. I just did plugs and wires a month ago and the are all in the correct spot. The issue is getting worse though. It is now stalling with out any electronics running unless I give it a little gas.
I haven't checked the coil packs yet, but it seems weird that one bad pack would cause every cylinder to misfire when it happens. Do you know the specs on testing them by chance?
From everything I've read I'm starting to think I missed seeing a vacuum leak. Wish I had a smoke tester so I could save the money taking it to the shop on Monday.
 
:violin:
Well one way to figure out what is wrong is to just let something go completley out. Was just driving to get some lunch and the 4runner died. Pulled into a parking lot and tried to crank but have nothing. No fuel pump sound when ignition is turned on so im pretty sure all of my symptoms were coming from a fuel pump going bad on me.

Anyone done a fuel pump in these? I believe the access to it is under the back seat but not sure? Will I have to drop the gas tank and is there anywhere I can hit to try and get it to start to get the 1.5 miles home so I dont have to tow it.
 
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