Rough Running Dually

[Desert1957]

IMO you must start at the very basics for engine problems..

1. Remove all spark plugs, do a compression check and record the numbers
if there is a problem here do not go any further before correcting the problem.(more then 20 psi difference between cylinders shows wear)

2. Go through the entire ignition system, check things you would not normally check, distributor shaft bushing wear, pickup coil , module , coil.

3. Set ignition timing correctly , be aware of the wire that needs to be disconnected for proper initial timing setting. TBI is like no other square body.

4. Check for vacuum leaks at the throttle body base and EGR, TBI engines will run bad with leaks

5. Check the fuel pressure, just because the engine is running doesn't mean it correct. 1 lb of pressure makes a huge difference on these engines


These are all starting points, remember, start with a healthy engine and you will find the problem, do not give up.

Desert