They seem to foul when climbing a hill i've changed wires, plugs, distributor, rotor, fuel filter and have used injector cleaners. Engine has 140k on it runs great otherwise

Have you checked fuel pressure ? Distributor cap and rotor ?
Is the check engine light on ?

Hi, you describe a chugging even on moderate hills, is your transmission shifting properly? It sounds like it's stuck in overdrive. Or a plugged injector or two that maybe push out fuel OK in warm up mode but not after. So if your transmission is downshifting when is should and you still have no power, I would have the injectors checked out. Good luck, chuckb

Have u checked the cadeletic converter. It can do funny things

What is the fuel pressure reading now? Has the distributor ignition rotor ever been replaced? They burn through and cause all kinds of problems. Also this could be spark plug wires leaking or shorting out to the engine block. I would take a very close look at the ignition systems condition.

Your testing so far seems to exonerate components #1 to #5, and #13.
Since you've already replaced a number of parts to address the problem, I thought I should try to be comprehensive:

Priority Action Part Type Cause
1 Inspect Ignition Switch - Improperly Connected or Faulty Ignition Switch.
2 Inspect Battery - Battery Discharged or Faulty.
3 Inspect Battery Cable - Coroded, Broken, Shorted or Poorly Connected Battery Cable.
4 Inspect Starter Solenoid - Starter Solenoid Faulty.
5 Inspect Starter Motor - Starter Motor Faulty.
6 Inspect Wireset - Worn or Damaged Spark Plug Wires.
7 Inspect Ignition Coil - Faulty Ignition Coil.
8 Inspect Distributor Cap - Loose, Cracked or Worn Distributor Cap.
9 Inspect Spark Plug - Incorrectly Gapped or Fouled Spark Plug(s).
10 Inspect Distributor Cap and Rotor Kit - Loose, Cracked or Worn Distributor Cap, or burned rotor contacts.
11 Inspect Fuel Tank - Fuel Tank Empty.
12 Inspect Carburetor - Worn, Faulty or Damaged Carburetor.
13 Inspect Fuel Pump - Faulty Fuel Pump.
14 Inspect Fuel Pump Strainer - Fuel Pump Strainer Clogged.
15 Inspect Fuel Filter - Fuel Filter Clogged.
16 Inspect Air Filter - Air Filter Clogged.
17 Inspect Fuel Injectors - Fuel Injectors Clogged/Inoperative
18 Inspect/Test PCM - Powertrain Control Module (Computer) defective - sending incorrect ignition/timing signals to fuel injectors
19 Inspect Fuel Rail - Fuel Rail leaking/broken causing inadequate/low fuel pressure.

Use a HEI (High Energy Ignition) tester to see if you have spark to your sprak plugs - if not, suspect Ignition Coil, Distributor Cap, or Distributor Rotor.

You've already eliminated the spark plug & wireset, distributor cap & rotor.
Sounds like your car needs a tune-up, specifically, the PCV (positive crankcase ventilation) valve, and/of the EGR (Exhaust Gas Recirculation) valve.

Components checked/replaced during a tune-up are:
air filter
motor oil
motor oil filter
breather filter
fuel filter(s)
fuel strainer
PCV valve
EGR valve
spark plugs
spark plug wires
ECM or distributor cap & rotor
cabin air filter
transmission oil filter
transmission oil
engine coolant
check all vacuum hoses and lines

Troubleshooting the no-start condition - from the 1990 Mitsu Mighty Max Repair Manual:

Priority Action Part Type -- Cause
1 Inspect Battery -- Battery Discharged or Faulty.
2 Inspect Battery Cable -- Corroded, Broken, Shorted or Poorly Connected Battery Cable.
3 Inspect Distributor Cap -- Distributor Cap Cracked or Burned.
3 Inspect Fuel Filter -- Clogged or Dirty Fuel Filter.
5 Inspect Ignition Coil -- Faulty Ignition Coil.
6 Inspect Wireset -- Worn, Damaged or Faulty Spark Plug Wire(s).
7 Inspect Spark Plug -- Incorrectly Gapped or Fouled Spark Plug(s).
8 Inspect Starter -- Starter Motor Faulty.
9 Inspect Fuel Pump -- Low Fuel Pressure.
10 Inspect Solenoid Switch -- Faulty Starter Solenoid Switch.
11 Inspect Fuel Pump Relay -- Faulty Fuel Pump Relay.
12 Inspect Fuel Injector Pressure Regulator -- Faulty Fuel Injector Pressure Regulator.
13 Inspect Ignition Switch -- Improperly Connected or Faulty Ignition Switch.
14 Inspect Starter Drive -- Faulty Starter Drive.
15 Inspect Fuel Injector -- Dirty or Worn Fuel Injectors.
16 Inspect Fuel Pump Strainer -- Clogged or Dirty Fuel Pump Strainerat.
17 Inspect Engine Control Computer -- Incorrect Operating Information Being Delivered and Sent From The EEC.
18 Inspect Fuel Tank -- Fuel Tank Empty.
19 Inspect Carburetor -- Carburetor Flooded or Faulty Choke.
20 Inspect Distributor -- Worn, Loose, or Incorrectly Installed Distributor.

Check your plugs, wires, distributor cap/rotor, fuel filter, and air filter.

If I had to take a guess, I would try replacing the Distributor Cap & Rotor, as well as the Fuel Filter. Also, try running some Gumout Fuel Injector Cleaner and a tank of good gas through it.

I hope this helps! Best of luck to you :-)

Best Regards,

James

You don't need to change the spark plugs since it has only 31.5 K. The plugs should last 60K. There is a an adjustment at the gas cable end at engine to increase the idle a little bit. You can increase rpm at idle to 600 RPM. Since your RPM at idle is low that why it is shaking at idle, red lights. Let me know it it is shaking at high speed ( 2500 RPM)

try to have your intake manifold and air filter cleaned. Also, try to replace the fuel filter. these are usually the culprits for the problem that you are experiencing.

Hello,
your problem appears to be the idle control motor located on the air intake manifold it is a small motor that goes bad quite often. Other items that can cause this is a bad /clogged air filter or a tune up (spark plugs and wires), or clogged fuel injectors. to clean the injectors you can buy a container of fuel system cleaner and pour it into the gas tank and as you drive it cleans the system.

Once the fuel system is cleaned via a tankful of cleaner & gas then the idle controller motor would be next on the list to be replaced.

Good Luck !
Rich Lilja