having a annoyimg problem,i have a 2000 f350 5.4 auto,that seems to stumble some of the time,when i accelerate. checked for codes no codes,anyone have heard of this deno

 

Does this happen when the engine was just started and is cold or all the time?

 

all the time, my brother in law said it might be detonation,not a stumble at all.sounds reasonable going to try higher octane,but was wondering if any one has ever heard of or had this problem? thanks deno

 

I could either be the mass air flow sensor to the idle air control valve. Try cleaning the element in the mass air flow sensor with a electrial contact spray cleaner. The IAC can also cause similiar problems. Usually they will cause hard to start or stalling when cold, but have been know to cause performance problems also.

 

what should i do just spray into the air inlet , dont really know how to clean it. deno

 

I'm not ssure of the set up on the trucks, I usually work on Crown Vics, but remove the inlet hose from the front the MAF. You should be able to see a wire element in the center. Sometimes you can actually see dirt or debis on the element. Spray the element with electrical cleaner and blow dry with low air pressure or allow to air dry. Also get a can of spray cleaner that is designed to clean throttle bodies. Ford doesn't recommend cleaning the throttle body since they put a special coating, but they do get a deposit build up. I clean the throttle body with a shop rag and spray cleaner. Just don't get too agressive. I you want to try to clean the IAC, remove it and use the throttle body cleaner. None of the above is hard to do and if you have any mechanical skills will be a piece of cake.

 

This could also be a bad coil. Sometimes you won't get a trouble code when this happens - if it only happens under load or at inititial take-off.

When this does occur - the only way to find it is to let the dealer perform diagnostics through a driveability test.

How many miles? When was the last time you changed the plugs? Have you changed them?