Slight stumble off idle, what's going on?

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Apr 2, 2006
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Slight stumble off idle, what's going on? UPDATED Original Post

Hey everyone, I've got a problem with my 96 LX450 I don't know what to do with.

Two days ago my wife drove the cruiser to the ballpark, ran perfect.

When she went to leave, it started but was shaking pretty bad. It sounded and felt like we were missing on 2 or 3 cylinders. It barely had any power.

I got it the mile home but it was pretty rough running.

I thought it might have been water or something in the dist. She claimed she didn't hit a puddle. I sprayed out the engine bay with a hose on Saturday and it ran JUST like this for a few minutes till the water got worked out of the distributor cap. I sprayed the engine while it was cold, not hot.


So I figured some water was in there somehow. I bought a code reader at walmart and it said it detected a misfire on cylinder 6.

I got a new cap and rotor today and pulled them off figuring they got burned by the water or something.

I replaced the cap which had a pretty bad burn on 6 and the rotor which was very pitted and corroded. I figured we'd be golden.

I started it and it's much better but there is still a stumble right off idle till you get to 1K rpm where it smooths right out.

It sounds like it's missing pretty badly on one cylinder but it's not throwing any codes. It stumbles and the engine shakes till 1K when it smooths out.

I tried pulling the wires off the distributor cap one at a time to see if any of them didn't make it worse, it seems like none of them make a difference.

When I have my wife drive it I can see the cats shake cause the engine is vibrating.


Any idea? I'd change the plugs but I can't find them.

I took the front cover off the plug wires and pulled up on the round thing that looks like its' going into cylinder one but it didn't come out. I pushed it back down in.

What should I be looking for?


OK here's an Update:

I followed IdahoDoug's advice and took off the airtube and the Mass Airflow Sensor. I sprayed water into the Mass Airflow Sensor just like he said to do and now it's even WORSE.

Just Kidding IdahoDoug! I Keed, I keed!

I did take the air tube off and per Doug's instructions blew out the MAF senson CONNECTOR with a little canned air meant for computers. It seems pretty dry in there so I just basically did it to be sure.

I also looked at the bottom of the tube where there are pleats and sure enough, there are some small cracks there. They are TINY though and I can't imagine they'd be leaking air.

Just to be sure I took some of the silicone Rescue Tape [this stuff is AWESOME] that I got somewhere and wrapped the hell outta the pleated section. I'm pretty sure it's airtight now. I used this stuff on a huge gash in my garden hose left by a lawnmower blade and it sealed it right up. It's rated to 500 degrees and I put 1/2 a roll on there so it's tight.

It's still missing like crazy though :crybaby: What next? I am going to pull the plugs as soon as I run down some wires and a factory service manual.

Is there a way to check the MAF and make sure it's not horked up? I have never seen a plug fail instantly like this did. I'd be tickled if it was a bad wire or something, I'm still hoping it's not the HeadGasket.

That would suck.
 
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Something similar happened to mine too. I did it the ol'school scary and dangerous way.
Turn engine on let idle.
Pull each plug wire one by one (using long, rubber coated pliers, and rubber gloves) and listen for the idle NOT to change.
The idea is that one plug or wire is bad and when you disconnect one that is good, the idle/sound will worsen. If it's the bad one that you pull, there will be no change.
So, you pull one off, and put it back in if theres a change and so on.
When you finally find the one that doesn't change the idle rumble you shut the engine off and pull the plug off and inspect it. I just dried mine up, had some moisture on the ceramic area, and she now purrs like a kitten.
Sorry if this method is frowned upon or whatever but it worked for me and besides that's how we fix stuff out in the desert.
 
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Something similar happened to mine too. I did it the ol'school scary and dangerous way.
Turn engine on let idle.
Pull each plug wire one by one (using long, rubber coated pliers, and rubber gloves) and listen for the idle NOT to change.
The idea is that one plug or wire is bad and when you disconnect one that is good, the idle/sound will worsen. If it's the bad one that you pull, there will be no change.
So, you pull one off, and put it back in if theres a change and so on.
When you finally find the one that doesn't change the idle rumble you shut the engine off and pull the plug off and inspect it. I just dried mine up, had some moisture on the ceramic area, and she now purrs like a kitten.
Sorry if this method is frowned upon or whatever but it worked for me and besides that's how we fix stuff out in the desert.

Would it not be eaisier to replace all of them rather than having one new and the rest are old? Although that is a great way to find out and fix the problem temporarily. ;p
 
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2 things to check if the spark plugs are good.

#1 - the large rubber hose feeding air from the air cleaner cracks in the pleated section - usually on the bottom from numbnuts pulling up the air cleaner lid instead of releasing the rubber hose. It's about a $90 mistake.
#2 - spraying water on the engine gets water in the mass/airflow sensor connector on the air cleaner tube. Open it and blow air in the connection (NOT IN THE SENSOR). This is a free mistake - don't put water on your engine.

DougM
 
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OK here's an update: I took it for a little drive tonight . It's actually missing pretty bad when it's under load. If it's in Neutral, it smooths out at 1K, but under load it's missing pretty bad all through the range.


It keeps throwing a miss detected on cylinder 6 code so that's where I'll start.


I will admit, I can't find where the spark plug boots are :confused:. It ls there a section in the FAQ on doing the plugs?


Edited to add: I will look at the mass airflow sensor on the air pipe too. Is it obvious which one it is? Should I just replace the sensor?
 
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Holy crap, man! If you cannot find your spark plug boots and remove them properly (without tearing them and resulting in a $100 purchase of new ones), then consider giving this to a professional. Nothing personal, but that's pretty basic, and thinking of you messing with the "mass airflow sensor" when I carefully stated in capital letters "NOT IN THE SENSOR" when I suggested you look at the CONNECTOR gives me the heebie jeebies. Screw up the sensor and you're looking at some $400 bucks, I bet.

You also blew right past looking at the rubber hose and went right into looking into a misfire on #6 code. This gives you a low score for considering/using advice.

I am sure I'll get dinged for this post, but really....

DougM
 
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Do you think a repair manual might help?

Curtis


a repair manual is first on the list tomorrow morning. I went to brent brown toyota this afternoon but what a bunch of morons.

I almost had to pry parts out of their hands. They were very reluctant to help any of their customers.

I am going to salt lake city tomorrow to find one.
 
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goneballistic- any response on whether or not you've checked the most basic of Doug's suggestions (also my bet, BTW) which is a crack in the plastic intake hose? Did you remove it and check for cracks? (The cracks can sometimes be hard to see, so check carefully). When you say it is fine in neutral but not under load, this is a classic sign of a cracked hose moving around. If the plug wires have not been changed, that would be good PM and may fix your problem, as well.
 
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GXO

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FWIW you can check the age of your plug wires by reading the date printed on them...RavenTai taught me this when he pointed and laughed at me for having 1996 on mine last year.
 
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Just had a similar problem with my other vehicle. Drove it somewhere and it was completely fine. Left 20 minutes later and all of a sudden it was running rough..rough enough to stall it self out because the RPMs would get so low.

Turned out it was the Mass AirFlow Sensor (MAF). The vehicle wasn’t getting the right mix of air/gas and it was running like crap. I got a MAF from the wreckers, haven’t put it on yet (been running without it for a couple of days and even without the piece, the car runs a lot better).

Might want to check that out?
 
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a repair manual is first on the list tomorrow morning. I went to brent brown toyota this afternoon but what a bunch of morons.

I almost had to pry parts out of their hands. They were very reluctant to help any of their customers.

I am going to salt lake city tomorrow to find one.
I doubt a dealer will have a Factory Service Manual in stock. If they don't, click on this link to order one.
 
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a repair manual is first on the list tomorrow morning. I went to brent brown toyota this afternoon but what a bunch of morons.

I almost had to pry parts out of their hands. They were very reluctant to help any of their customers.

I am going to salt lake city tomorrow to find one.

Brent Brown was your first mistake. I prefer Menlove, call and talk to Brad, he will take care of you. Mark Miller has also been very helpful. Tom is the main guy at the parts counter. If you need to look at an engine that is out of the rig to practice on let me know.
 
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Brent Brown was your first mistake. I prefer Menlove, call and talk to Brad, he will take care of you. Mark Miller has also been very helpful. Tom is the main guy at the parts counter. If you need to look at an engine that is out of the rig to practice on let me know.

If it is the MAF, I may have an extra.
 
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Holy crap, man! If you cannot find your spark plug boots and remove them properly (without tearing them and resulting in a $100 purchase of new ones), then consider giving this to a professional. Nothing personal, but that's pretty basic, and thinking of you messing with the "mass airflow sensor" when I carefully stated in capital letters "NOT IN THE SENSOR" when I suggested you look at the CONNECTOR gives me the heebie jeebies. Screw up the sensor and you're looking at some $400 bucks, I bet.

You also blew right past looking at the rubber hose and went right into looking into a misfire on #6 code. This gives you a low score for considering/using advice.

I am sure I'll get dinged for this post, but really....

DougM



:doh:that's what I get for posting from my blackberry :D

sorry I wasn't clearer Doug. The problem I'm having with the spark plug boots is that on my 81 they are hanging out in space, I can pull over, pop the hood, reach in an pull one off without even touching anything else.

On this thing they are so buried under intake and emissions stuff, I can only see a couple of them. Plus they don't look like normal boots, so it's a little more confusing that the ol' FJ40.

And I did take your advice and pulled the MAF connector on top of the air hose and it looks dry and clean. I haven't blown any air in there but I didn't put anything in the MAF sensor either, based on your advice.

I haven't pulled the airhose to check for cracks yet, just cause it's pouring outside and I'm working from home. As soon as the downpour stops, I will pull the hose and check it. If it's got any cracks, I will put silicone tape on it till I can get another one.


So when I said I'd start with cylinder six, I meant assuming there is no crack in the hose and the MAF connector was dry.


Is there a decent way to check the MAF and see if that's it? I am hoping I didn't get water into it and toast it. Is that something that will dry out or is it possibly hosed, knowing the connection itself seems to be OK?

Man, it bugs me having this truck running poorly. This is the second Land Cruiser which I've bought and then had start to have problems soon after I bought it. My other one was an FJ40 with 130K on it. I'm working on a new engine for that one right now....
 
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OK there is an update in the first post. Basically blew out the MAF connector per IdahoDoug and wrapped the air tube pleated section in silicone tape just for good measure.

Still missing like mad. :crybaby:
 
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Just had a similar problem with my other vehicle. Drove it somewhere and it was completely fine. Left 20 minutes later and all of a sudden it was running rough..rough enough to stall it self out because the RPMs would get so low.

Turned out it was the Mass AirFlow Sensor (MAF). The vehicle wasn’t getting the right mix of air/gas and it was running like crap. I got a MAF from the wreckers, haven’t put it on yet (been running without it for a couple of days and even without the piece, the car runs a lot better).

Might want to check that out?


how can I bypass the MAF to see if this is the issue? It looks like an integral part of the hose. If I pull out the connector: dead truck. It only runs about 2 seconds.
 
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haven't changed the plug wires yet, nobody in town has them. I'm headed to SLC tomorrow to get some new wires. I already got new plugs.

At 140K, even if they are not the root cause, they should probably be replaced.


I'll update after I get that done..


Thanks for the input guys. it helps
 

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