My wife's 2000 4Runner will intermittenly not accelerate at all. 3.4 V6 5VZFE, auot trans 4X4 181,000 miles. No trouble codes. Sometimes will pop from exhaust. Feels like it is not getting any fuel at all. Stop vehicle, turn ignition off and back on again, runs OK. Have cleaned MAF sensor wires. Is this a bad tps? Thanks for any and all help in advance.