1992 gen 1 mx6 mazda 6cyl.hesitation ,misfire,flatspot.replaced plugs,leads,rotor cap,fuel filter etc

Based on the symptoms you've described, it sounds like your car may be experiencing a misfire. Here are some potential causes and solutions:

1. Ignition system: A faulty ignition system can cause a misfire. Check the spark plugs, ignition coil, distributor cap, and ignition wires for any signs of damage or wear. Replace any faulty components.
2. Fuel system: A clogged fuel filter or malfunctioning fuel pump can cause a misfire. Check the fuel filter and pump to ensure they are functioning properly. Consider cleaning or replacing the fuel injectors as well.
3. Carburetor: Since your engine is carburetor'd, a dirty or faulty carburetor can also cause a misfire. Clean or rebuild the carburetor as needed.
4. Vacuum leaks: A vacuum leak can cause a misfire. Inspect the vacuum lines and hoses for any signs of damage or cracks, and replace any damaged components.
5. Timing issues: If the engine timing is off, it can cause a misfire. Check the timing belt or chain to ensure it is in good condition, and check the ignition timing.

that should give you codes on computer, but look at ignition system cap ,rotor,plugs, wires, fuel filter

TPS sensor and IAC sensor.

The rubber hose from air filter box to throttle body commonly splits along one of it's grooves and will open up on acceleration and cause a hesitation

If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
I know the elm327 plastic 1.4 can help you reset the code....
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

means misfire in #5 cylinder. found this for you. hope this helps
Common Problems That Trigger the P0305

• Worn out spark plugs, ignition wires, coil(s), distributor cap and rotor (when applicable)
• Incorrect ignition timing
• Vacuum leak(s)
• Low or weak fuel pressure
• Improperly functioning EGR system
• Defective Mass Air Flow Sensor
• Defective Crankshaft and/or Camshaft Sensor
• Defective Throttle Position Sensor
• Mechanical engine problems (i.e.-low compression, leaking head gasket(s), or valve problems

Common Misdiagnoses

• Fuel Injectors
• Oxygen Sensor(s)
• Power Train/Drive Train problem

The OBD-1 two digits trouble codes listed 'code-17' as:
Oxygen sensor.

This means that the fuel and ignition systems performance are in need of attention.

1.Distributor Cap: remove the 3-bolts holding the distriboutr to its body.
2. Inspect the distributor cap for cracks, and the roror-button is not worn or broken.
3. Inspect the distributor-cap terminals are not corroded or charred. Replace if charred. Clean them out if corroded.
4. Check the distributor-rotor for cracks or corrosion on its tip, and lesser spring tension.
Replace as necessary.
5. Reverse steps 1-4 to re-install distributor cap. Be sure to remove and replace the plug wires from the old distributor-cap to the new distributor-cap one-by-one. If not, the engine would not run.

Fuel-Filter:
1. Undo the top clips holding the fuel-filter hose, and undo the lower clips also.
2. Take out the fuel-filter from its mount.
3. Replace the fuel filter as necessary.(please not the way it was mounted) Reverse removal for installation.

Replace the oxigen sensor and the cat.If its not eusing oil then i dont think your engine needs to be replaced.Also check your air filter is not dirty and add some injector cleaner.to the fuel.Good luck hope that was helpfull.

COIL.?

Check the gap between the prong and contact of the spark plugs. Your local parts store can look up the gap measurement and should have a gap tool you can buy for really cheap, sounds like that may be the issue.