Running rough when driving
 

Hello everyone

My engine is running rough when driving the car, no power and feels like it's Running on 3 cilinders.
When it's running stationary all is good, even when putting the engine under load in natural is running pretty fine.
I am currently running a Stromberg 97 and a fsignition with automatic advance.
The timing is good and it's having ignition on all 4 sparkplugs.
The jets in the carb are still to big but I drove it like this a while back and had no problems, just had toch clean the sparkplugs allot ofcourse.

I can't wrap my head around it.

Re: Running rough when driving
 

Try replacing the plugs.

Re: Running rough when driving
 

Could be an issue with your electronic ignition. Not sure if they can fail that way though, never used one.

If it were stock I'd say your points weren't opening far enough. Start simple, check the plugs.

Re: Running rough when driving
 

If your spark plugs are black to the point you have to clean them chances are they are fouling especially if there are champions

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Re: Running rough when driving
 

I would change the plugs first.

Had the same sounding problem many years ago. I bought a car that had been just tuned up. Ran great for about one hundred miles than started to feel like it was loading up. Took the plugs out and cleaned them. Everything was good for about fifty miles, than problem started again.

Took out plugs and check there part number. They where not right plug for Model A. Got new set of correct plugs, Champion 16Y, everything has been running great since.

Re: Running rough when driving
 

It all boils down to fuel flow and spark! Is there good flow from the gas tank, not full of rust plugging up the carb? Is there an inline fuel filter (aftermarket) that is plugged up?
Fuel flow problems can cause an engine to run perfectly at idle or light load but under heavier load (and fuel flow needs) just not getting all the fuel needed.

If you resolve that gas flow is not the issue and that the carb is clean and working properly, you are down to your electronic ignition. (in my opinion)

Re: Running rough when driving
 

Thank you for all the replies, I will check which sparkplugs are in the model A at the moment.
I cleaned the gastank and put a resin in it, I am Running a fuelpump and a fuelregulator set at 1,5 psi. The inline filter is also not clogged.I will start nu changing the plugs.

Re: Running rough when driving
 

I checked the plugs and they are already Champion W16Y.

Re: Running rough when driving
 

Check your fuel pump, just to make sure it is constantly on. If not, it will periodically run you out of gas, or make it feel like you are mis firing every once in a while.

Re: Running rough when driving
 

I had a similar problem. Changing the coil helped!

Re: Running rough when driving
 

Do you have the proper coil for the FSI ignition are you still 6 or 12 volt do you have resistant plug wires

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Re: Running rough when driving
 

I had a pertronix 12 volt coil (3 ohms),12 volt system and a resistor wire from the coil to the cap. The plugs still had the brass connectors. When I put my "B" distributor back in, it still missed until I changed the coil. I am now working on a modified Honda distributor with centrifugal and vacuum advance for it. With a 7:1 head it is quite sensitive to timing.