I just did a full tuneup on her. (recently bought the truck and love it except for the lack of power lol) plugs wires cap and rotor fuel filter pcv valve air filter. all plugs and wires tight and new. all plugs gapped .032. (ngk v-power) It was sputtering before the tuneup and is no better now! Also seafoamed the truck. all within the last 24 hours. no miss fire hesitation or anything around town, runs awesome, until I get above 60mph.

So I'm thinking maybe o2 sensor? Tps seems perfectly fine, smooth idle no hesitation. exhaust flow is excellent too, so I'm currently ruling out the cat.

Anyone have any ideas? I can't see just throwing new parts at my 20 year old truck (even though she's just a baby mileage wise 147k)

 

Egr? Possible Egr opening or closing at wrong times. Try unhooking the vac line (plug it)to it and take it down the highway. Possible Vac leak.....

 

Ahh! didn't think about egr. Is this a common problem on these engines? I have plenty of experiance with fords, but this is my first toyota. Vacuum seems to be fine, tested with starting fluid and all seems leak free.

 

Yea i'd say egr and if thats what it is just plug the vac line to the egr and leave it alone forever.... unless you wanna take it off and put block off plates............or unless you wanna pay some big cash for a new shiny one..... it really does not effect performance at all on these vehciles its for emissions... and our trucks don't require emissions tests no more....lol so yea

 

Awesome. gonna go give it a whirl! Thanks!

 

well unfortunately its not the egr. unplugged vacuum line and its still no better.....

 

hmmm.... and you said it sputters on highway.... you don't have any probs with it in anyother area? no codes or nothing? possible cat clog.... but usually this would be more noticeable with that..... its hard to tell. sure its got no vac leaks anywhere? exhaust leaks? o2 sensor?

 

yeah o2 was my thought originally. well I'll check that next. also no codes on ecu

 

How are you checking for vacuum leaks?

 

On older 4runners/pickups the vehicle speed sensor (vss) is a mechanical reed switch in the speedo, and when it gets old the signal can get noisy, which is interpreted by the ecu as excessive speed and so it activates the governor (fuel cut) feature. Not sure if that's causing your trouble, but it's worth a look.

Here's a tech article on the issue: http://www.motor.com/article.asp?article_ID=271

And some info on identifying the vss wire: http://www.the12volt.com/installbay/...TID~98493~PN~1

 

was checking for vacuum leaks with the old starting fluid method (fire extiguisher right next to me too lol) no vacuum leaks at all! impressive to me actually considering the 3000 vacuum lines!

Also as a correction, the pcv was not changed. I bought the new one and CAN NOT GET THE OLD ONE OUT!!!!!! what a pita! is there any trick to changing them on a 3vze?

If the vss is the issue would it cause a bouncy speedo as well? Mine does bounce a good bit when cruising. Also will it get worse, because my highway only sputter is become more of an issue and is starting at lower speeds now (40ish)

 

The vss prob wont cause the speedo bounce, more likely the other way around. A dry cable may be causing both problems. Try lubricating the cable with a non-wax type motorcycle chain lube or replace it.

 

well it seems that the pcv valve was the issue! bought the new one with the rest of the tuneup parts and then missplaced it, so i assumed i had replaced it. Its a real pita to replace. I ended up getting ticked and pulling the Intake manifold off to do it lol
cleaned the intake manifold out anyways so it was worth it.

Truck runs so much better now!