Mitsubishi Repair: Engine cutting out, difficulty starting, throttle position sensor, manual tranny

Question
1992 Mitsu Eclipse 1.8L, manual tranny, 180K+ miles.

Here goes:  I was stopped at a traffic light a couple of days ago, let out the clutch and the engine just quit on me -- no sputter, nothing.  I could not get it re-started.  The engine would crank but the car acted as if it was not getting fuel, so I had to get it towed.  The check engine light did not come on.

Once I got the car home and started to work on it, it would start once in a while, but not every time.  Once I get the car started, sometimes it will idle erratically for a time and sometimes I have to apply pressure on the pedal to keep it going. If I try to get it out on the road, it will just suddenly die and then it is the will of the car whether it wants to start.  After one of the attempts to drive around the block, the check engine light finally came on.

I've taken the ECM out and checked it per your instructions on the capacitor page and found no visible damage to the board and a slight smell that might signal leaking capacitors. I'll get a new one or replace the capacitors just to be safe. But so far, the ECM has consistently given me a functional reading -- a 14 and a 15 -- throttle position sensor and an idle speed control motor position sensor.  I've checked the TPS with an ohmmeter and it reads just under 4K resistance at idle position, but the resistance doesn't vary when I move the throttle around.  From that information, I'm pretty sure the TPS needs to be replaced.

So after all of that exposition, here's my question -- would those bad sensors be enough to cause my engine to just cut out and not re-start?  What are some other possibilities of what would cause these particular symptoms?

Thank you very much,
Ben  

Answer
Ben,
Sounds like you're on the right track.  A bad TPS and ISC motor sensor will cause the problems you're experiencing.  Your ECM relies on the readings it gets from the TPS to be sure there is enough air getting to the engine.  If the ECM gets a bad reading and thinks not enough air is getting to the engine, it will cut the fuel supply, hence causing your engine to die.  Your ISC relies on the reading from the TPS as well.   It detects from the ECM if the throttle plate is closed or not.  If it thinks the throttle plate is fully closed, it will start allowing air to enter the engine and bypass the throttle plate.  If your ECM starts seeing some unmeasured air coming from ISC and detects the throttle plate is open (which it may not be due to a bad TPS reading), the ECM will again cut the fuel supply to avoid the risk of detonation.

So, replace your TPS first and see if that cures your problem.  Also, check the resistence readings of your ISC to be sure that is within spec.  If your problem still occurs, check your Intake Air Temperature (IAT) sensor in your air filter housing.  Be sure your spark plugs, plug wires, and distributor are all in good shape as well.  Replace your fuel filter if you haven't done so in the past 2-3 years.  
Good luck!