I think it's the tps going out.
The TPS can be tested with a digital voltmeter.
The center terminal of the TPS is the output terminal.
With the ignition key in the ON position, check the
TPS output voltage at the center terminal wire of the
connector. Check this at idle (throttle plate closed)
and at wide open throttle (WOT). At idle, TPS output
voltage should be greater than .350 millivolts and
less than 900 millivolts. At wide open throttle, TPS
output voltage must be less than 4.5 volts. The output
voltage should increase gradually as the throttle
plate is slowly opened from idle to WOT.