Slight miss?
 

hey guys maybe someone here can offer some direction. Was out on the boat today and at low rpm the engine developed a slight miss. When I give it throttle it stumbles a tiny bit then is fine, come up on plane and runs out fine. It runs fine from about 1200 rpm up. Below that it misses, doesn't seem to be the iac valve, it feels and sounds like a fuel problem but could be ignition..the motor is a 2001 7.4mpi

Re: Slight miss?
 

You can check with a timing light if it is the ignition and if it relates to a specific cylinder. May be somewhere on the secondary side of the ignition, dist cap, plugwire.

Re: Slight miss?
 

Ive had a similar problem, hard starts poor idle and slow response at low RPM. If your tack is jumping at all replace the coil..worked for me.