2001 toyota tundra v6 misfire

in january i posted i had a misfire in cyl 3. i swapped ignition coils around, still in cylinder 3. i replaced spark plugs, no change, i replaced spark plug wires, no change. i have been putting seafoam in my tank every time i get gas , but no change. it seems to be a heat related problem. when i crank the truck up in the morning it runs great, no misfire, but when i turn the truck off and then crank it up it misfires, cyl 3. compression is ok. had someone mention the ecm may be bad. my question is when the truck tells the spark plug to splark, where does that command come from? is it the ecm? i thinking whatever tells the plug to spark may be bad. any help or advice is appreciated. thanks. if the truck sits for several hours and i crank it , it runs for for a while then starts misfiring. there are times when im driving it and it is misfiring, and it quits misfiring for a bit but then starts back up.

 

First thing that comes to mind considering the difference in running performance based on heat is that the plugs may be the the incorrect ones, or an incorrect heat range. If you purchased off Amazon or online, there are counterfeit plugs that do not perform well. Tundras like NGK. It also will help others help you if you list the actual codes the truck is throwing.

 

Rats. Literally. Check for wire damage?

 

previous thread and last post @clint77 made from a month ago that might help those assisting....

2001 toyota tundra v6 | Toyota Tundra Forum (tundras.com)

Not saying it's not a heat vs cold thing, but misfires are "2 trip detection logic".

 

Yup, simple test for this could be to move the plug from cylinder 3 to another cylinder and see if it tracks.

Also worth noting, I think there were two different plugs for the V6? I swore someone just posted on here not long ago that the damn dealership gave him the wrong plugs, and the wrong V6 ones they gave were half an inch longer, deeper into the cylinder than the right V6 plugs.

Then he found other issues, and the truck stopped starting after. Anyway ... something to test. Because @frichco228 is correct, so many cases of counterfeits on scAmazon and fleaBay it's not worth buying there anymore.

 

Here's that thread where dealership gave the wrong plugs, for extra reading: https://www.tundras.com/threads/spark-plug-differences.106500/

 

Have you done a compression test yet? Worth a look... see what's going on.

 

New plug wires, that’s a new one for me

 

V6.

 

I’d swap injectors between #3 and another cylinder and see if the misfire follows.

 

I tend to agree with land fill. You may have a partially plugged injector. The mixture is richer on a cold start engine, which explains why it acts up when your truck goes into warm-up. You didn't mention in your posts when the misfire started. Did you do any repairs to your tundra? Or did it start on its own. I would smoke the motor through intake to be sure you have no vacuum leaks. Also thoroughly check exhaust for leaks. Any of the above can cause a lean misfire. A mechanic buddy of mine had a similar problem on a 99 Lincoln navigator, turned out to be a bad injector the cylinder that was throwing code. Let us know what you find. Moose.

 

If he's been using Seafoam every tank of gas, I doubt a clogged injector would still be clogged after a few tanks. Seafoam is pretty solid choice for cleaning out injectors.

 

I meant to post this a while back. Turns out it was a fuel injector. He swapped the fuel injector on three and one and the misfire jumped to one. So it was the fuel injector. Replaced it and it’s been running fine