Misfires! 5VZFE

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blockhead

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My sons 2000 was running rough and getting a cylinder 6 misfire. Replaced plugs with NGK Laser Platinum dual electrode, wires with NGK, air filter, a couple vacuum hoses, ran a can of sea foam through it and a tank of premium. Ran GREAT. For a day.

Now multiple cylinder misfires (3, 5, and 6) and running rough at all speeds.

Injectors? Wrong plugs?
 
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blockhead said:
My sons 2000 was running rough and getting a cylinder 6 misfire. Replaced plugs with NGK Laser Platinum dual electrode, wires with NGK, air filter, a couple vacuum hoses, ran a can of sea foam through it and a tank of premium. Ran GREAT. For a day.

Now multiple cylinder misfires (3, 5, and 6) and running rough at all speeds.

Injectors? Wrong plugs?
Click to expand...

Wires are installed correctly. 1 to 4, 3 to 6, 5 to 2. Although the plugs come pregapped checks the spark plug gap 0.44.. part #'s Denso K16TR11, NGK BKR5EKB-11, toyota part 90919-01192
 
blockhead said:
My sons 2000 was running rough and getting a cylinder 6 misfire. Replaced plugs with NGK Laser Platinum dual electrode, wires with NGK, air filter, a couple vacuum hoses, ran a can of sea foam through it and a tank of premium. Ran GREAT. For a day.

Now multiple cylinder misfires (3, 5, and 6) and running rough at all speeds.

Injectors? Wrong plugs?
Click to expand...


Where did you get the laser platinums from? Amazon or a autoparts store? If Amazon they could be knock offs and not real NGK.


Sent from my iPhone using Tapatalk
 
After driving around for a day the new spark plug wires could of rubbed or burned a hole in them causing a short from touching something hot or sharp during installation. Also, something could be fouling the spark plugs and it took a day of driving to foul the new spark plugs. Leaking head gasket can cause fouled plugs. The fact that you now have codes in both cylinders makes me think that probably isn't the problem but I would check and rule that out. Any unexplained coolant loss or pressure in the overflow tank?
 
Sparky 97Runner said:
After driving around for a day the new spark plug wires could of rubbed or burned a hole in them causing a short from touching something hot or sharp during installation. Also, something could be fouling the spark plugs and it took a day of driving to foul the new spark plugs. Leaking head gasket can cause fouled plugs. The fact that you now have codes in both cylinders makes me think that probably isn't the problem but I would check and rule that out. Any unexplained coolant loss or pressure in the overflow tank?
Click to expand...

Wires look good. Never have to top off coolant.
 
The fact that it ran great for a day after changing plugs, wires, hoses and sea foam is what's got me stumped. I wouldn't think it would run great at all if the hoses or wires were misrouted. I can't figure how sea foam would only temporarily clean up a misfire. I hate throwing parts at problems but you could throw another set of plugs in there and see if the problem temporarily goes away again. Then you'd know that something is fouling the plugs. Hopefully someone will chime in about the sea foam.
 
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Do a compression test. Rules out the possibility of poor compression. Head gaskets can cause rough idle and multiple cylinder misfires while carbon build up can affect the valves. Head gasket issues are rare unless you overheat the engine.

Check that you don't have a dirty maf sensor while your at it
 
My only thought is it could be fuel related, perhaps at the injectors but I'd start cheaper personally. When was the last time the fuel filter was changed? Thinkin the seafoam maybe had somethin to do with it
 
Running great one day and not the next is usually a sensor that's out of whack or failing. I would recommend cleaning the MAF for starters. It's highly unlikely a plug failed after one day. I suppose anything could happen though.

Also look into replacing your upstream O2 sensor if you never have. The older, narrowband sensors used to have a service interval of 90K miles per Toyota's FSM. They got rid of that in 96 but it's still the same part. If you have a Toyota wideband, they are close to $150 though so up to you if you want to try that or not.
 
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So yesterday I pulled the air intake again and double checked the routing of the wires. I did a resistance test on one coil which it failed(?). After looking at all the coils some had poor looking contacts and some had excessive IMHO dialectic grease on the springs in the coils. Installed 3 new Denso coils. That wasn’t it. Back to cylinder 6 misfire. :redbrick:

I did clean the MAF sensor when I changed the plugs and wires the other day.

As it was late Saturday afternoon, I surrendered. I’ll drop at a reputable shop Monday for a likely compression test and whatever other diagnostic services and repair. The good news is that everything I did was due for replacement anyway.
 
blockhead said:
My sons 2000 was running rough and getting a cylinder 6 misfire. Replaced plugs with NGK Laser Platinum dual electrode, wires with NGK, air filter, a couple vacuum hoses, ran a can of sea foam through it and a tank of premium. Ran GREAT. For a day.

Now multiple cylinder misfires (3, 5, and 6) and running rough at all speeds.

Injectors? Wrong plugs?
Click to expand...

crankshaft sensor :)
 
glad you found the problem.
for anyone else chasing a misfire I found mine to be a coil pack was going bad and replacing it fixed mine.
 
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