I have a 96 4runner 3.4L (5 SPD)550,000miles and lately its been bucking under accleration.yesterday, while i was driving it started bucking and died, i let it sit, started it again and another mile of so of driving and it died again. BUT heres the weird thing......the bucking is tied to engine speed. at around 3500 rpm the car will not acclerate anymore and acts as if it has a rev limiter. NOW this is why i feel like it is the regulator, i had the fuel pump swapped about a year or two ago,and yesterday the car backfired twice, i fell like the regulator is busted and allowing too much fuel through. ANY HELP OR ADVICE IS APPRECIATED.

 

Check your timing belt. Make sure the crank bolt isn't coming out.