90 Lumina Euro throttle drops out

[CatiaDr]

1990 Lumina, 202K miles, 3.1l, always dependable (until now).
The car WAS in the following state: It only started on warmer days (replaced o2 sensor, cleaned throttle body and now it starts on colder days) It was running rougher (replaced Plugs and Wires which improved rough running but not completely). It coded 22 and 35 (replaced TPS and MAP sensors) Occasionally the low coolant warning lights (but it is not low). I replaced the computer for good measure and paid a mechanic to chase down some low voltages (2 wires were nearly severed). The car is now in the folowing state: The car idles a little rough, but is running. When it is being driven, occasionally the throttle stops working and the car returns to an idle, regardless of the forward speed or throttle position. If I keep the accellerator pedal still, eventually the engine will rev back up, (sometimes with a little kicking and bucking like I am tapping the throttle). If this occurs at lower speeds, the car has a tendency to die. I have verified fuel pressure at 35psi at an idle, and it increases to 40psi as throttle increases but have no way of testing pressure when it is stalling/bucking. The engine is quite oily, so I plan on cleaning grounds but is this scenario familiar to anyone?

[jeffcoslacker]

Do a "sweep test" of the throttle position switch with an ohmeter as you open and close the throttle slowly. Any dropouts in the reading will cause this syptom. Otherwise I'd guess a fuel delivery problem.

[CatiaDr]

I will try that. It has been replaced, but better safe than sorry.

[jeffcoslacker]

Yeah, it's best not to rule out something new, you can end up chasing your tail. Anymore, those are the first things I check. Take a hard look at the wiring and plugs, too.