Typically,
Well check the basics, fluid level , condition, but typically these eratic symptoms are caused by a malfunctioning input, ie Tps, VSS,
OR
It just dont like hauling Jap crap around ????
E4od.
Gas eng ?
3 or 4sp tranny ?
Anyhoo, Stab in the Dark going to say thats its a 460 gas eng, with a E40D puker
And whats causing the problem is a Throttle position sensor, or Vehicle Speed sensor,