OBD1 code 33?

33 - Throttle position sensor noisy/harsh on line

I've never seen a throttle position sensor code described this way, but Ford always does things a little differently. I never approve of replacing random parts as a diagnostic step, but in this case the cause can only be a dirty sensor or loose / corroded connector terminals for it. Since these sensors are relatively inexpensive, I'd start with installing a new one. Erase the fault code, then, if that code comes back, we'll have to dig deeper.

If you'd want to get more involved, you can use an oscilloscope to look at the signal voltage coming off that sensor. It should rise smoothly from roughly 0.5 volts to about 4.5 volts as you sweep the throttle from fully closed to fully open. The actual voltages are not important. It's the smooth changes we have to see, with no "noise", or glitches on the waveform.

You can watch the signal voltage with a digital voltmeter too, but the glitches are just about impossible to see. The voltage must transition very smoothly as the throttle blade is opened and closed.

You can also read the TPS signal voltage on a scanner, but 1990 and older Ford Engine Computers can be fussy when trying to view live data. The fastest way to approach this is to just pop in a new sensor.

Let me know what happens, then we'll figure out where to go next.