4Runner V6 engine problem

[johnwruss]

Any ideas? after driving about 10 highway miles engines begins to run rough and lose power. I can give it full throttle and it runs out with full power such as it is. Get on the city street and cruise at say 40 mph in 4th gear and it sputters and jerks intermittently.
Have changed rotor, cap, wires and coil. Dealership cleaned injectors and I have been using 44K in tank. Even drained tank and cleaned filter. Muffler was also replaced and also air filter.
Dealership also did all diagnostics possible and could not find problem but acknowledge there is a problem. What next? Is it electrical, fueling or maybe converter problem or a sensor somewhere. What should I try next?

[Wright]

I have a 96 4wd Tacoma with 3.4 L V-6 and automatic transmission, and I experience similar symptoms. Mine seems to stutter around the point when the transmission lock engages and disengages (around 50 mph) and usually when I'm driving on a slight incline. It seems the transmission doesn't know whether it wants to engage or disengage. I've flushed my transmission (to ensure it's not caused by old ATF) and I lubricate my driveshaft frequently (like once a week). I haven't eliminated the problem entirely, but lubricating the driveshaft seems to alleviate the problem. Hope this helps.

[RICHIE]

i had the same problem also.i found it to be a loose battery connection once.then after about a year it started again and it was the egr vacuum modulator...about 40 bucks.it is bad if you can suck air into the bottom port and there should be a strong resistance if you blow in to the bottom port.another way to find out if its bad is to make sure your egr valve is working properly.when your truck warms up the egr valve will get hot to touch,i noticed on mine when the modulator went bad i had lots of water in the lines and the egr wasnt getting hot...so if ya have water in vacuum lines i would say its the modulator..good luck

[dczv]

I have had the same problem and chaged out everything both you guys listed and it still did the same thing. I pulled my distributor and found the bearing at the bottom of the shaft to be bad. This is what fixed my problem. The engine had 125k on it.