Misfire issue

I've got the 4.7 has rans amazing for the time I've had it decided to replace the plugs went with platinum gapped them to .031 per the owners manual old plugs were worn down beyond belief, didn't run right with new plugs a lot of bucking a stuttering so I went with autolite copper plugs same gap but it still runs like crap I noticed that the old plugs were so worn they measured .065 gap anyone have any suggestions should I try gapping the new plugs to .065

 

Where did you buy the plugs? Which exact plugs did you buy?

Any check engine light and/or codes.

 

Autolite 3923 got them from O'Reilly's didn't gap them at first cause they were supposed to be pregapped

 

And no codes or lights

 

Some pre-gapped plugs you can damage just by attempting to gap. Iridium plugs being one example. But I'm doubting that's the issue.

If you have no codes and no check engine light, where are you coming up with "Misfire"? Misfires normally cause a flashing CEL.

Did you inspect the coil packs for cracks on the spark plug tubes? Ensure the boot is intact?

 

Yeah I've looked over all the coils they look fine, I was fixin to go ahead and replace them but honestly unless something else went bad while I was replacing them like the fuel filter knowing my luck wouldn't be the first time

 

Stupid question #1, have you tried reinstalling the old plugs to see if the bucking still happens? Just curious if a rollback may take plugs out of the equation.

Stupid question #2, did you remove a battery cable while working?

Stupid question #3, did you remove the connectors from the coil packs before removing, or leave them attached and just flip the coils up and out of the way?

I've been f'ed over by Oreilly enough that I don't buy things there anymore. I also know nothing about the Autolite plugs you bought, or how they compare to what Toyota tells you is best to use with their engine. I also don't buy Autolite parts. I see the manual calls for:

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I buy NGK plugs fairly exclusively for all my vehicles, I learned the hard way enough, NGK has never been disappointed since. This is what NGK calls for, last item is same as manual; I personally go with pre-gapped Iridiums:

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Oh, and in no way am I tell you to buy new plugs. I think it stands to reason if you tried two plugs and got same result, there's potentially something else going on. Unless the plugs you're choosing are truly not compatible.

 

Have not reinstalled the old plugs so a few months back I removed one of the plugs to test it and see if they need to be replaced run fine before that I put the plug back in and then that one started having issues so I went to O'Reilly's I bought the 3923 auto light plug and put it in place of the one that was causing issues ran fine, yes I removed the battery cable, the first time I just left the coils connected and moved them out the way after that I completely removed them found it was easier, I had ngk platinum plugs but they were doing the same thing as what it's doing now

 

Did you do anything else? Or just change plugs?

Any time you remove the battery cable for more than 5-10 minutes, you trigger a relearn. There are cases where the engine will run like shit afterward in that case, especially if you're one of the poor suckers who has a K&N kit, an oiled air filter and/or use crappy filters that caused throttle body gunk buildup. Alternately, if you clean the throttle body and DO NOT pull the negative batt cable, and the engine is trying to run with "dirty TB" parameters, it'll run like shit just the same.

I don't think plugs are your issue here. I don't think you're misfiring, because the ECU would be flashing your check engine light, as it does for misfire conditions.

I would be checking your throttle body OR letting the truck idle for 10-15 minutes to see if it recalibrates.

 

I cleaned the throttle body few months ago not sure I'll have to keep checking stuff I know the truck runs fine for the first few minutes then as I drive it more the bucking gets worse but I'll let it idle and see if a few days will help it relearn

 

If it's bucking, and you're not throwing codes or flashing the CEL, I'm hard pressed to believe it's misfiring. Did you scan for pending codes when it's bucking like a bronco?

 

My scanner doesn't show me pending but I know someone who has a solid scanner

 

Ok so good news narrowed it down to where it's coming from I used a scanner with live feed was able to monitor misfires from every cylinder and #1 has a random misfire but no codes and no pending codes just happens every few minutes if I hold the brake with my foot lightly on the gas

 

Swap coil pack on cylinder 1 with the one on cylinder 3.

See if the misfire follows. If so, replace coil pack that's now on cylinder 3. I recommend Denso coil packs, since other brands have been so problematic for others. Don't buy on scAmazon or fleaBay.

If no follow, it's not the coil packs; consider swapping those plugs and watch. If not, it may be other item; bad injector, or intake gasket.

 

Also ... you may want to check all your vacuum hoses, the ends, look for any wallered out, cracked at the ends, etc.

 

I just thought of that it's the coil I saw your message right as I was reading the live data as soon as I moved the coil the misfire moved

 

Great minds think alike. It's the coil. Denso replacement. RockAuto or Summit Racing will get it to you pretty quickly and as cheap as others, I'd hope.

 

Already on it thank you for your help

 

I would add, that although I would replace just that coil first, to confirm the problem, I would replace all of them soon after. Electronic parts like that, that usually are installed all together, and work identical lengths of time, often fail in rapid succession.

 

I have had personal experience on a tundra specifically where that wasn't true, at least on the older first gens. It can take a stupid amount of time to get these trucks to throw a misfire code sometimes.

@Abaux6 don't cheap out on parts store coil packs. Stick with denso.

 

Maybe it's a VVTi vs non-VVTi thing. I swear the VVTi engines will flash at any-damn-thing.

 

Same here. I've also had the check engine light turn off for a while even though the misfire was still there. It was also my understanding that a flashing check engine light indicates a severe misfire whereas a normal misfire will just have a solid light.