1995 3.1 ciera motor problem

motor idles and runs fine to 3500-4000 rpm's, then it quits like the computer shuts it down, it will upshift and run again to the same rpms and do it again(it shuts down like a speed limiter). There are no trouble codes, what can it be?

Do you mean it just shuts down or stutters like a rev limiter in neutral?

not a stutter like rev limiter, shuts down like my s10 did when it hit its speed limiter, but this is happening at 35mph in 1st gear, then again at 60-65 in 2nd.