How make 94 Chrysler LHS run better?

Take it to a local garage and have the computer system scanned for stored codes. Have them check the car out to see what needs to be done. 50K and no maintenance, not good. things are going to start going bad. $$$$$$$$$ out the window unless you are a mechanic and the labor is free.

dont feel bad even the new ones have those problems

First off, change the oil and filter. This is very important. You need to change the plugs and set the gap after you clean the t-body at the air intake . Spray some kind of carbon cleaner in the throttle body and on the inside and on the ISM idle speed motor. I use a old tooth brush to scrub the inside of the t-body. Clean off the throttle plate(butterfly valve) run the engine after doing this to clear out the cleaner, this should make it idle better

Performance mods are not a very good idea on a vehicle that is nearly 17 years old. You would be just asking for problems.

However there are a few things you could and should do.

First, a good tune up. New plugs. Nothing fancy. Fancy plugs do little to improve a stock engine. Use the same make and type plug originally installed from the factory. Usually platinum plugs. Install a good set of spark plug wires at the same time. Again, nothing fancy but don't go cheap either. The parts store will usually offer a few sets of plug wires with various prices. Select a mid grade set and they will work fine.

TIP: When installing the plugs put a small amount of anti seize compound on the threads. A little goes a long way. Don't get any on the electrodes. This will make them easier to remove in the future. Put a small amount of dielectric grease in the spark plug wire boots. This will help seal out moisture and make them easier to remove in the future.

Change the air filter. Again, nothing fancy. The stock air filter will supply the engine with all the air it will need.

If the car is equipped with a mass airflow sensor clean it with Mass Airflow Sensor cleaner. Don't use anything like carburetor cleaner or you will destroy the sensor turning a $5 repair into a $50+ repair.

It may be a good idea to replace the oxygen sensor(s). These should be replaced from time to time.

Add a can of Sea Foam to the fuel system. This will clean out your fuel injectors. After the first tank of Sea Foam replace your fuel filter. Every couple of tanks of fuel add about 1 ounce of Sea Foam per gallon of fuel. This will keep your fuel system and intake clean.

Spray some Sea Foam Deep Creep into the throttle body while the engine is running until it stalls. Allow the engine to sit for several minutes and restart. This will clean the carbon from your plenum, intake manifold, and around your valves. The engine will be difficult to restart and will most likely smoke for a few minutes. This is normal.

About 50 miles before your next oil change add about 1 ounce of Sea Foam per quart of motor oil. Drive normally. This will help clean sludge deposits from inside your engine. If you oil pressure light starts to come on, immediately change your oil and filter. This would be because the Sea Foam washed enough sludge that it may block your oil filter. However this is an extreme condition and would be unlikely to happen.

With the age of this vehicle I would change the transmission fluid filter and transmission fluid.

Keep a close watch on your tire pressure. Too low tire pressure creates increased rolling resistance. Keeping the tires inflated to the correct pressure will improve performance and fuel economy.

If you can do all of the work yourself you could get buy with doing all of this work for less than $150. At least double this amount if you must pay a mechanic to do the work for you.

spark plugs. ignition coils if it has any. brakes. all filters. if its carburated you should clean that.

Go back in time and slap the bejesus out of the engineers who designed it.