I've got a 2000 4runner v6 that had been running fine till it started getting cold. When I first start it up in the morning it starts fine, idles fine, drives good till I get to the highway and when I start to quickly accelerate at around 45mph or so it sort of stumbles/misses a couple of times. If I keep the same acceleration it goes through it and does fine. If I accelerate a bit more it stumbles more. All this stops after its been running for about 10-15 minutes and is up to temp. I'm a bit stumped as to what it could be. Naturally I'm thinking plugs/plug wires and maybe a sticky EGR valve if it has one? Anyone familiar with these symptoms and have a better idea as to what to check?

Thanks!

 

first thing is clean the MAF. this can cause a lot of goofty issues
and it is by far the easiest to eliminate. clean it. drive 1 tank (so the ecu can adjust).

then see what else occurs.


after that, others will have better advice

 

MAF is spotless as I clean it about every 3 months or so with MAF cleaner.

 

has the timing belt been done? PCV valve($8 OEM), coil pack?

i got luck with the same problem you have, it was a cracked spark plug and boot, $60 fix.

does it throw you CEL you the motor misses?

 

New timing belt about 5k miles ago. No pvc or coil pack change though. I'm planning on changing plugs and wires this weekend.

No CEL. It only misses after the engine is cold (several hours) and just for a few seconds while accelerating around 40-50mph. Each time I have to accelerate it will do that until after 10 mins or so of driving then it doesn't do it again. When the weather was warm it never did it.

 

i had the same problem as well...i started with the fuel filter (cheapest) then went to new spark plugs and wires. after a while i finally got a code for a misfire on cylinder two. changed out the plugs and it runs like a charm now. try it out.

 

I was going to change the plugs and wires this weekend. Funny, I thought about the fuel filter on the way in to work so now that you mention it, I'll change that as well. Hopefully it gets it! Tks!

 

Same issue under HARD acceleration on the HWY... new plugs, fuel flter, properly cleaned MAF sensor, changed PCV valve... yet I have original plug wires, will swap soon wire set soon..
I 'm thinking possibly a Bad fuel injector?

 

yep, that's a thought as well. Fuel, throttle, or electrically related to acceleration. I'm gonna scan it as well when it's doing it's missing to see if any codes or conditions come up that will point more accurately to something. I'll probably do that after I change the plugs/wires, fuel filter and PCV valve. I've got a nice list of things to check now...

 

there is tons of threads on this subject--a search could yield you much knowledge.

 

Any word yet on this? My 4runner is having the EXACT same issue but its a 2.7L. I've done plugs, cleaned MAF and TB, PCV, and replaced the fuel filter with no help. I too am thinking wires or an injector. Is it possible a sensor could be causing this like a coolant temp sensor or even an o2 sensor??? Let us know what works!!!

 

if you think injectors, then do the seafoam thing first because injectors ain't cheap.

 

Well, I changed my plugs and PCV valve and now I'm no longer have the problem! The odd thing was the back 2 spark plugs on the driver's side (Which are a bit hard to access) were only in a bit better than finger tight. Not wobbly but zero effort to get them out. The plugs actually looked ok but that doesn't mean much. The PCV valve was a bit sticky but not really bad though it could have been stickier cold. I suspect it mostly likely the plugs not being torqued in all the way or just a bad plug. I got a new fuel filter but the old one is rusted on pretty good. Tried PB and Liquid Wrench but it's still stuck. I really don't want to get new fuel lines but it may come to that....

 

If you really want to get those lines off--try 50/50 mix of acetone and tranny fluid (Not the tranny you find on the corner type of fluid). Works great--I used it alot on my 72 Jag--and its cheaper....just keep applying it everyday

 

I'll give that a go! I'm not in a hurry so re-applying is no biggie!

 

I had that hesitation prob on my 90 4Runner and it was a cracked distributor cap.