Sorry for the bad luck, hope you resolve it soon and reasonably inexpensively!!

If the links on the timing chain are stretched precisely at the cam position where those cylinders are involved in the timing.


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Thanks Doc. I appreciate the support.

crank position sensor: timing belt slipped?

Does it do this all the time = misfire?

Hey Ruckerz, Yeah, it can't work like that. There are no specific links that line up for a particular cylinder. Yes, when you time it they have to be in time but after the engine is started the links don't line back up with the marks on the gears every revolution. In fact, going from memory when I was a Nissan tech, you line up the silver links on the chain with the marks on the gears, then it takes something like 90 some revolutions before the links line back up with the marks again. Thanks for your effort again.

Hey Captsolo, Well it's a V6 so it can't be the timing belt. It's possible the chain could've jumped a few teeth but at this point I don't think so. Crank position sensor is something I plan to look at. Even it seems somewhat unlikely though since it's only affecting 2 cylinders. But no, the misfire doesn't happen all the time. It only happens when it's under a load. It will do it at idle if it's in gear, and it does it when driving under even a small load. At a steady cruise with almost no load it doesn't do it at all. And it's both #1 and #2 cylinders. They both misfire at exactly the same time. And they both starting doing this at exactly the same time. It feels just like every ignition related misfire I've ever dealt with. That's what is making this so difficult. Thank you for your reply and for any ideas you may have.

I dunno. Depending on the build date and mileage you probably know the head gasket issues these cars have. It’s unclear whether or not it’s been done for your car but I’ve read of cases where the owner machined they head because it over heated and or screwed it up on the way out. Engine never runs smoothly again. And machining heads is a no no for these engines. Just a thought but sounds like you need more diagnosis like ripping off the valve covers and or timing chain cover to see what’s going on inside?


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You’re right but you’d be surprised it doesn’t take many revolutions to get back to the original section of the chain . Less than 20.


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Hey Ruckerz,, You're right, I don't know for sure about the head gaskets. I don't think they've been changed but I have no way of proving it. But, this car has run perfectly for 7-8k miles since I got it. Then all of a sudden it began misfiring. And it's always cyls 1 and 2 every time, and no other cylinder is affected. So, I don't think it could be head gasket or timing chain related. If a chain is stretched at any point it's going to retard the timing on the cam(s) it drives at all times. Of course the vvti can offset some of that but either way it will affect all cylinders equally. Again, I do appreciate your input and if you happen to think of something else, by all means let me know. I think my next step is going to be to call Identifix. They saved by butt a number of times when I had my shop and ran into something unique like this. Thank you again!

I think you're right about the chain, if it was stretched or skipped a tooth you would be getting a cam/crank position mismatch fault, not a misfire fault.

That's true. I do still wonder if maybe something has happened to a couple of the teeth on the reluctor wheel that the crank sensor reads off of. Unfortunately, it's still going to be a little while before I can check this stuff. I'm stuck in NC at our vacation camper and the 4runner is at home in SC. Thank you for your input!

How did the plugs look ?

I am placing my bet on the injector, 5 bucks worth.
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It may turn out to be injectors. I'm still thinking something more unusual, like a wiring problem or bad computer. I'll be sure to post on here when I finally find out what the problem is.

I am glad I am not the only one having this issue with the 4.0 engine. I am working on a 2005 4Runner Sport V6 4 Wheel Drive. This has been ongoing for 8 months already. Change something and it is good for a couple of weeks. Then back to same issue. It first started out around 40 mph under load and now it is hesitating at other speeds. The engine light has not been coming on again since the throttle body was replaced about 2 months ago. The hesitation at times is not too bad and at others it's bad. If anyone has suggestions and/or if you come up with solution please let me know. Thanks in advance.

Aside from swapping the coils and injectors to another cylinder and seeing what happens, i'm going to go out on a limb here and say its possible that you have a head gasket problem and a small amount of coolant is getting into at least one or both of those cylinders. Do you notice the misfire at cold start up at all? After driving it for a while, you can pull one or both of those plugs and look for any steam coming out. You might have to hold a mirror over the plug hole when doing this. Something else you can do is drive it for a while and then park it overnight. Pull either #1 or #2 plug or both and use a borescope to see if you can see any traces of coolant on top of the pistons. Good luck finding the issue!