Hi I have ba dedicated gas it has started to miss and hesitate under load Have changed coils and plugs and converter ?????? Any ideas where to go from here

Possibly a bad ignition coil. I just went through this issue. Most coils just fail. I have now seen one that was putting out very weak spark. The spark was a white color when I had a spark plug hooked up to it. It should be a hot orange or blue spark. The spark was too weak to fire under load conditions. Good luck.

A P0301 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #1.

Symptoms may include:
* the engine may be harder to start
* the engine may stumble / stumble, and/or hesitate
* other symptoms may also be present

Causes: A code P0301 may mean that one or more of the following has happened:
* Faulty spark plug or wire
* Faulty coil (pack)
* Faulty oxygen sensor(s)
* Faulty fuel injector
* Burned exhaust valve
* Faulty catalytic converter(s)
* Running out of fuel
* Poor compression
* Defective computer

Possible Solutions:
* If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
* 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.

Test it and send us news.

P0304 Code - Cylinder #4 Misfire Technical Description Cylinder #4 Misfire Detected
What does that mean? A P0304 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #4.
FB.init("dd7d9e9681341cde77587bc6a2029f6f"); OBD-Codes.com on Facebook SymptomsSymptoms may include:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

Causes A code P0304 may mean that one or more of the following has happened:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• Defective computer

Possible Solutions If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
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
.

distributor under the rotor and cap, if not the rotor and cap (or ignition pack-coil if its not cap and rotor.)

You need to check the Ignition coils , as whencoils are week , some times does not show on dash or diagnose system. probably best to change your coils

its a valve sticking or a coil breakdown

Have you checked the coils? It has three above the rear valve cover right?

Check for spark on number 3 from the coil.

It is probably a bad coil, have someone put it on a computer and see what cylinder is missing. The coils go bad all the time on the 5.4's

Here are some good causes and its worth to take in consideration:
Clogged fuel filter?
Insufficient fuel pressure due to a faulty fuel pump?
MAF sensor?
Catalityc converter?
ECU module?
does the CHECK ENGINE show up?
Get back to me.