Engine missing

R

razerface

Member
1998 limited. Started it to go to work and sounded like 5 cylinders. I bought new denso iridium plugs and installed them. No joy,,still misses. No codes.

How do i tell which cylinder is missing? It is not a perfect steady miss, but is easy to hear at the tailpipe and noticable when driving. When sitting still in driveway, i can rev it up and it sounds fine.
 
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You should be using the required dual ground plugs, if you're not supercharged.
 
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Conventional wisdom is to remove the connection to each plug in turn while it's running. When the non-functioning plug wire is removed, the missed cylinder will not be missed, so to speak. Every other plug removal should result in a noticeable added missed cylinder.
I'm not sure of the logistics of doing this with the intake removed on the 5VZ engine, however.
 
pluton said:
Conventional wisdom is to remove the connection to each plug in turn while it's running. When the non-functioning plug wire is removed, the missed cylinder will not be missed, so to speak. Every other plug removal should result in a noticeable added missed cylinder.
I'm not sure of the logistics of doing this with the intake removed on the 5VZ engine, however.
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It will not run with the intake removed, i tried that. Is there a way to make it run with it off?
 
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turbo8 said:
You should be using the required dual ground plugs, if you're not supercharged.
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The bosch iridiums i replaced lasted 207,000 miles,, and it looks like they were still good, since replacing them did not help. I saw no reason to change plug type. Why do you say the other plugs are required?
 
razerface said:
The bosch iridiums i replaced lasted 207,000 miles,, and it looks like they were still good, since replacing them did not help. I saw no reason to change plug type. Why do you say the other plugs are required?
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Toyota says they are required.
It says in the owner's manual and there's a sticker on the timing cover that says to use dual ground.
The 5vfze 3.4 has a waste spark ignition setup, so it runs smoother with the dual ground. Use the plugs they come from the factory with and don't try to out think it.

It looks like you take good care of your '98 based on the 347k miles mention in your signature, so good for you :bigok: but go with the factory ones now.
A lot of people mention missing and vibration issues fixed simply by using the proper plugs.
Maybe you somehow had a 'good' batch of the wrong plugs for 200k (who knows?)
 
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When you say no codes do you mean the Check Engine light isn't flashing or you checked it with a scan tool?

A scan tool should show misfires.
 
When my '99, V-6, developed a miss that rapidly got worse it turned out that the ignition coils were progressively failing. I ended up replacing all three and all was fine again.
 
alumarine said:
When you say no codes do you mean the Check Engine light isn't flashing or you checked it with a scan tool?

A scan tool should show misfires.
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Scan tool showed no codes. I drove it about 75 feet when it started missing, put it back in garage and got in another vehicle. Maybe it has not had time to throw code? I will drive down the road tonite a mile or so, and recheck.
 
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razerface said:
Did it throw a code for that?
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I had a bad coil (coils?) and your problem sounds like it could be that too. Mine was missing at higher RPMs but I've had bad coils cause poor low rpm running too in the past.

I never got any codes on mine, but I replaced the coils and it was good as new. It is an expensive proposition to replace the coils though if you're not sure it's the problem.

You ran one set of plugs for 207k miles? That's not going to help your coils any!
 
I just called toyota dealer. They gave me 2 choices for plugs.
Fk20hr11----iridium. And
K16tr11. -----dual ground.

He says his book calls for either one.
 
Don't overlook your wires...
Get a scanner that can read pending codes. sometimes that will point out the issue prior to a CEL.
 
Denso lists a heat range of 16 for that application.
20's might be too cold.
I wouldn't necessarily trust a parts employee.
Some know their stuff, some don't.

I wonder if the 20 is for supercharged applications?

How do the plugs look?

You could get one coil from a wrecker and swap it around.

Find My Part | DENSO Auto Parts
 
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The plugs i took out looked fine. I believe i could keep running them,,but already bought and installed new ones. I don't know why you guys think they would be hard on the coils running that long? The iridiums don't erode and change gap like the regular plugs do. At least mine did not.

I do have a brand new coil i bought when i thought i had a coil problem, but an injector was the problem,,and i just put the coil on the shelf instead of returning it. I suppose that will be the project for the weekend if i get no codes out of it.
 
I_bRAD said:
Did you try the new coil on #6?
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Yes i did. In fact, it is still on there since it did not cure the miss,,i did not want to take the time to change back until the injectors were here,,,then do it all at once. It was nice having that laying on the shelf.
 
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