223 boggs in third at 45mph


New member
To really know if the fuel system is delivering enough fuel at WOT you should install a fuel pressure gauge to see if the pressure drops when the engine boggs.
If not then I would look at the main jets.
This is where an Air/Fuel ratio gauge really helps out.
Yes I tested pressure after the pump and at the carb after the pressure regulator while running and it didn’t indicate any loss of pressure when the engine boggs.


New member
Well… problem fixed I think! Went back and reset the float in the carb, turned the fuel regulator up a psi and found two loose spark plugs. Not sure for sure what the cause was but all of those fixes definitely helped. This thing goes like snot now. I’m not winning any drag races but it easily gets to highway speed and more. Thanks for all of the suggestions and help.


Top Poster
Staff member
Supporter 2021
Supporter 2019
Congrats on finding the cause and fixing your 223 that was a very simple fix, In my OPIN those two loose spark plugs were the likely cause of all your power loss at above 45 MPH speeds since it was then only runing on four cylinders instead of six as you were heading to the higher speeds those two spark plugs from vibration our other reasons lost their grounds to the cylinder head and just stopped firing. Next time you take out those spark plugs get yourself a good round wire brush and do a good cleaning on the heads spark plug seats and threads so there's no rust, dirt, or crude that will help them keep a really good ground.

Been having a seemular problem recently on my late model pickup the 5.4 had 3 loose spark plugs one were center electrode was compleately disintegrated got that one change out for new and ran almost perfect again, I think one more of the plugs #4 may also be damaged or just worn out am still have a slight intermitant miss fire. I was able to tighten that plug up which end helped but wasn't able to get it out to install a new one due to the carbon build up been soaking it though so can try again. In the past the Ford dealer had changed out the original plugs to install a fresh set at 78,000 they broke those three getting them out damaging those threads some in the aluminum heads enough so that those 3 plugs won't stay tight between the recommended 75,000 mile plug changes. The thing isn't very much fun to work on compared to the ease of working on a 223. You have your 223 set up with some great parts should be an excellent runner. As you drive it and test it some more you may find the need to go back down to the 3.0 PSI on your fuel pressure regulator to the Weber as you had it before. Best of luck.